The sovereignty of (the Westminster) Parliament is a doctrine whose cardi-
nal importance to the British constitution would be diļ¬cult to exaggerate. As
the ā˜keystoneā™ of the constitution (as Dicey expressed it), what is meant is that
the doctrine is no less than ā˜the central principleā™ of the system, ā˜on which all the
rest dependsā™ (to quote from the deļ¬nition oļ¬ered in the Oxford English
Dictionary). While it is elemental, however, in a comparative sense it is also quite
unusual. Most constitutional orders do not confer supremacy on statute. Most
constitutional orders confer supremacy on the constitutional text itself, a text
that normally binds not only judges and governments but also Parliaments. The
British constitution is unusual in not stating that Acts of Parliament are subject
to constitutional limitations. This unusualness has caused a good number of
commentators and, in recent times, also some judges to suggest that, notwith-
standing the fundamental role that the doctrine has played in the past, the time
has come for it to be at least reconsidered, if not discarded altogether. We will
explore some of these arguments in the pages that follow.
In this part of the chapter, ļ¬rst we consider the Diceyan orthodoxy and, in
particular, the way in which it was accepted in the leading twentieth-century
case law. Then we move on to examine the impact on the sovereignty of
Parliament of the break-up of the British Empire. When Dicey wrote, the
Westminster Parliament made laws not only for Britain but for a large number
of colonies and Dominions across the globe. How may the territorial extent
42 British Government and the Constitution
of parliamentary sovereignty be reduced? If Parliament may make or unmake
any law whatsoever, could it make a law granting independence to a colony and
subsequently repeal that law, withdrawing the grant of independence and
reasserting British rule over the territory? In the third section we consider the
question of whether Parliament is able to bind its successor Parliaments. Is every
Parliament equally sovereign, or may Parliament today limit the way in which
Parliament tomorrow may make laws? In the ļ¬nal section of this part, we
consider three contemporary challenges to the doctrine of parliamentary
sovereignty: the challenge that comes from the United Kingdomā™s membership
of the European Union, the challenge that comes from the inclusion since 1998
within our legal system of fundamental rights, and the challenge that may be
beginning to come from the common law itself.
(a) Diceyan orthodoxy
Both the positive and the negative aspects of Diceyā™s formulation of the sover-
eignty of Parliament are illustrated by the following cases.
Cheney v Conn  1 All ER 779 (Ungoed-Thomas J)
A taxpayer appealed against an assessment to income tax made under the
Finance Act 1964. One of the grounds of the appeal was that, since the money
would be used in part for the construction of nuclear weapons, and since (it was
argued) such use was contrary to international law, the illegal purpose to which
the statute was being applied invalidated the assessment. This argument failed;
in dealing with it Ungoed-Thomas J said:
What the statute itself enacts cannot be unlawful, because what the statute says and
provides is itself the law, and the highest form of law that is known to this country. It is the
law which prevails over every other form of law, and it is not for the court to say that a par-
liamentary enactment, the highest law in this country, is illegal.
That statute prevails over treaties binding on the United Kingdom was
reaļ¬rmed by the House of Lords in R v Lyons  UKHL 44,  1 AC
976, Lord Hoļ¬mann saying:
The sovereign legislator in the United Kingdom is Parliament. If Parliament has plainly laid
down the law, it is the duty of the courts to apply it, whether that would involve the Crown
in breach of an international treaty or not.
On the other hand, the courts acknowledge a duty to interpret statutes, if
possible, as being in conformity with international law and treaty obligations,
and we shall see that this interpretative power may be very far-reaching (below,
43 The ideas of the constitution
The supremacy of statute has also been sustained in a negative way by a con-
sistent judicial disclaimer of any power of interference with Acts of Parliament.
In Manuel v Attorney General  Ch 77, 86, Sir Robert Megarry V-C said:
I am bound to say that from first to last I have heard nothing in this case to make me doubt
the simple rule that the duty of the court is to obey and apply every Act of Parliament, and
that the court cannot hold any such Act to be ultra vires. Of course there may be questions
about what the Act means, and of course there is power to hold statutory instruments and
other subordinate legislation ultra vires. But once an instrument is recognised as being an
Act of Parliament, no English court can refuse to obey it or question its validity.
Plainly the instrument before the court must be recognised as being an Act
of Parliament. In R v Secretary of State for the Environment, ex p Hammersmith
and Fulham London Borough Council  1 AC 521, 562, Lord Donaldson
MR, after allowing for the impact of European Community Law upon parlia-
mentary sovereignty, said:
Parliament has a limitless right to alter or add to the law by means of primary legislation,
enacted by the full constitutional process of debate and decision in both Houses on first and
second readings of the Bill, committee and report stages and third readings, followed by
Royal Assent. The result is a statute and in relation to statutes the only duty of the judiciary
is to interpret and apply them.
Resolutions of one or of both Houses of Parliament do not have the force of
law. Accordingly in Bowles v Bank of England  1 Ch 57, Parker J held that
a resolution of the House of Commons was not enough to empower the Crown
to levy income tax: only an Act of Parliament could authorise taxation.
But if an Act is expressed to have been enacted by Queen, Lords and
Commons, the courts will not inquire whether it was properly passed, or rep-
resents the will of Parliament. This was aļ¬rmed in a famous dictum of Lord
Campbell in Edinburgh and Dalkeith Railway Co v Wauchope (1842) 8 Cl &
Fin 710. In this case it had been argued in the court below that a private Act
of Parliament was inoperative because notice to those aļ¬ected by it had not
been given as required by parliamentary standing orders. (Private Acts com-
monly aļ¬ect private rights and are subject to a special parliamentary proce-
dure.) Although this argument was abandoned in the House of Lords, Lord
Campbell expressed a clear view on the point:
[A]ll that a Court of Justice can do is to look to the Parliamentary roll: if from that it should
appear that a bill has passed both Houses and received the Royal Assent, no Court of Justice
can inquire into the mode in which it was introduced into Parliament, nor into what was
done previous to its introduction, or what passed in Parliament during its progress in its
various stages through both Houses.
44 British Government and the Constitution
Some years later in Lee v Bude and Torrington Junction Rly Co (1871) LR 6
CP 576 there was again a challenge to the validity of a private Act, this time
on the ground that the promoters of the Act had fraudulently misled Parliament
as to the facts and the promotersā™ true purposes. In rejecting this argument,
Willes J said:
Are we to act as regents over what is done by parliament with the consent of the Queen,
lords, and commons? I deny that any such authority exists. If an Act of Parliament has been
obtained improperly, it is for the legislature to correct it by repealing it: but, so long as
it exists as law, the Courts are bound to obey it. The proceedings here are judicial, not
autocratic, which they would be if we could make laws instead of administering them.
Despite these unequivocal rulings the question of the validity of a private Act
was once more argued in the courts in an important case in the 1970s.
British Railways Board v Pickin  AC 765 (HL)
In Acts of Parliament by which the old railway companies acquired land for
laying railway lines it was provided that, if the lines should be discontinued, the
land taken was to revert to the adjoining landowners. In 1968 the British
Railways Board promoted a private bill which would extinguish the rights of
reverter; it was passed as the British Railways Act 1968. Pickin, who had
acquired land adjoining a railway line that had been discontinued, brought an
action in which he asserted that the relevant provision (section 18) of the Act of
1968 was invalid and ineļ¬ective to deprive him of his rights in the track. The
Act, he maintained, had been improperly passed through Parliament as an
unopposed private bill, in that notice had not been given to aļ¬ected landown-
ers as required by standing orders, and Parliament had been misled by false
statements in the preamble to the bill that notices and plans of the land had been
On the application of the Railways Board these contentions were ordered to
be struck out of the pleadings as an abuse of the process of the court, but they
were restored by the Court of Appeal as raising a triable issue. The Boardā™s
appeal against this decision was allowed by a unanimous House of Lords.
Lord Reid: . . . The idea that a court is entitled to disregard a provision in an Act of Parliament
on any ground must seem strange and startling to anyone with any knowledge of the history
and law of our constitution, but a detailed argument has been submitted to your Lordships
and I must deal with it.
I must make it plain that there has been no attempt to question the general supremacy
of Parliament. In earlier times many learned lawyers seem to have believed that an Act of
Parliament could be disregarded in so far as it was contrary to the law of God or the law of
nature or natural justice, but since the supremacy of Parliament was finally demonstrated by
the Revolution of 1688 any such idea has become obsolete.
45 The ideas of the constitution
The respondentā™s contention is that there is a difference between a public and a private
Act. There are of course great differences between the methods and procedures followed in
dealing with public and private Bills, and there may be some differences in the methods of
construing their provisions. But the respondent argues for a much more fundamental differ-
ence. There is little in modern authority that he can rely on. The mainstay of his argument
is a decision of this House, Mackenzie v Stewart in 1754.
The Court of Appeal had been persuaded that in Mackenzie v Stewart the
House of Lords had refused to give eļ¬ect to a private Act obtained by fraud.
Lord Reid re-examined this old and ill-reported case, and concluded that it had
been decided by putting a particular construction upon the Act in question, and
not by holding it invalid. Lord Reid continued:
The function of the court is to construe and apply the enactments of Parliament. The court
has no concern with the manner in which Parliament or its officers carrying out its Standing
Orders perform these functions. Any attempt to prove that they were misled by fraud or
otherwise would necessarily involve an inquiry into the manner in which they had performed
their functions in dealing with the Bill which became the British Railways Act 1968. . . .
For a century or more both Parliament and the courts have been careful not to act so as
to cause conflict between them. Any such investigations as the respondent seeks could easily
lead to such a conflict, and I would only support it if compelled to do so by clear authority.
But it appears to me that the whole trend of authority for over a century is clearly against
permitting any such investigation.
The respondent is entitled to argue that section 18 should be construed in a way
favourable to him and for that reason I have refrained from pronouncing on that matter. But
he is not entitled to go behind the Act to show that section 18 should not be enforced. Nor
is he entitled to examine proceedings in Parliament in order to show that the appellants by
fraudulently misleading Parliament caused him loss. I am therefore clearly of opinion that
this appeal should be allowed.
The House of Lords expressly approved what had been said by Lord
Campbell in Wauchopeā™s case and by Willes J in Leeā™s case (as quoted above).
Lord Simon of Glaisdale relied in particular upon the privilege of Parliament
declared in Article 9 of the Bill of Rights 1689 as disallowing any questioning of
parliamentary proceedings. (See below, p 129.) He also drew attention to a prac-
[I]f there is evidence that Parliament may have been misled into an enactment, Parliament
might well ā“ indeed, would be likely to ā“ wish to conduct its own inquiry. It would be unthink-
able that two inquiries ā“ one parliamentary and the other forensic ā“ should proceed concur-
rently, conceivably arriving at different conclusions; and a parliamentary examination of
parliamentary procedures and of the actions and understandings of officers of Parliament
would seem to be clearly more satisfactory than one conducted in a court of law ā“ quite apart
from considerations of Parliamentary privilege.
46 British Government and the Constitution
Lord Morris was mindful of Parliamentā™s character as the supreme judicial
body in the land ā“ a medieval conception not yet quite extinct:
It would be impracticable and undesirable for the High Court of Justice to embark upon an
inquiry concerning the effect or the effectiveness of the internal procedures in the High Court
of Parliament or an inquiry whether in any particular case those procedures were effectively
Jackson v Attorney General  UKHL 56,  1 AC 262
The normal procedure for the enactment of statute is that a Bill must be ā˜readā™
and passed three times by each House ā“ Commons and Lords ā“ and will then
receive the royal assent (see in more detail chapter 9). Thus, Acts of Parliament
are formally made by the Crown, the Lords and the Commons acting together.
Since the Parliament Act 1911, however, the Commons and the Crown have
enjoyed a limited power to legislate without the consent of the House of Lords.
If the Commons passes a Bill which is then repeatedly rejected by the Lords,
after a certain period the bill may none the less proceed to receive the royal
assent (and thereby become an Act) despite the opposition of the House of
Lords. The eļ¬ect of the Parliament Act 1911 was, for most bills, to replace the
Lordsā™ veto over legislation with a power to delay the legislation. The one excep-
tion written into the statute is that a bill to extend the life of a Parliament (ie, to
postpone a general election) continues to require the assent of both Houses.
These arrangements were amended by the Parliament Act 1949, which reduced
the length by which the House of Lords may delay a bill from two years to one
year (much shorter periods of delay apply to ā˜money billsā™, such as the govern-
mentā™s budget, but that need not concern us here). The 1949 Act was itself
passed under the Parliament Act procedure. Since 1949, only four Acts have
been passed using this procedure: the War Crimes Act 1991, the European
Parliamentary Elections Act 1999, the Sexual Oļ¬ences (Amendment) Act 2000
and the Hunting Act 2004.
In Jackson v Attorney General  UKHL 56 a challenge was launched to
the constitutional validity of the Hunting Act 2004 and the Parliament Act 1949.
Jackson is a very important case in the developing law of the sovereignty of
Parliament, and we shall consider it in detail later in this chapter. For now, what
concerns us is solely the point raised in Wauchope, Lee and Pickin: namely, do
the courts have the jurisdiction to examine whether a purported statute is
properly a statute? The Attorney General did not seek to argue that the challenge
to the 1949 and 2004 Acts was non-justiciable. The Government knew that the
hunting legislation was controversial and considered that a clear verdict from
the courts as to its validity was preferable to there being any continuing doubt
about the matter. Accordingly, he conceded that the courts did have juris-
diction. The courts accepted, albeit in some instances with qualiļ¬cation, that he
was right to do so.
47 The ideas of the constitution
Lord Bingham: . . . Like the Court of Appeal . . . I feel some sense of strangeness at the
exercise which the courts have (with the acquiescence of the Attorney General) been invited
to undertake in these proceedings. The authority of Pickin v British Railways Board 
AC 765 is unquestioned, and it was there very clearly decided that ā˜the courts in this country
have no power to declare enacted law to be invalidā™ (per Lord Simon of Glaisdale at p 798).
I am, however, persuaded that the present proceedings are legitimate, for two reasons. First,
in Pickin, unlike the present case, it was sought to investigate the internal workings and
procedures of Parliament to demonstrate that it had been misled and so had proceeded on
a false basis. This was held to be illegitimate . . . [his Lordship cited the quotation from Lord