On 23 June 2016 the UK voted in a referendum to leave the
European Union. While non-binding, the new government has said that
the Brexit vote will be given effect.
The response in the UK to the referendum result was an
outpouring of emotion and a cessation of effective government and
opposition. However, within hours of the result, David Cameron
resigned and a new government was quickly formed under his
replacement as Prime Minster, Theresa May. As was always going to
be the case however, the real result of the referendum has been to
stir the debate further, not to put an end to it. Mrs May has said
that "Brexit means Brexit", but that is like saying
'breakfast means breakfast', and is no definition at all.
The debate about the precise terms on which we leave the EU and our
relationships with the rest of the world will rage for years,
possibly decades. All we know for certain at the moment is that the
real process of withdrawal from the European Union, i.e. the
triggering of Article 50 of the Treaty of the European Union, will
happen in March next year.
Article 50 provides that it is for the United Kingdom to decide
to withdraw from the European Union according to its own
"constitutional requirements". The United Kingdom has no
codified constitution however, and there are competing theories as
to what our constitutional requirements actually are. The
Government is of the view that it can trigger Article 50 utilising
its power under the Royal Prerogative, which allows the Government,
on the Sovereign's behalf, to conduct foreign affairs and enter
into international treaties.
The other view is that Parliament must decide to trigger Article
50, either by means of an Act or otherwise.
This is of course a political rather than legal argument; those
who are in the Royal Prerogative camp will tend to be Brexiteers.
Those who are in the Parliament camp are likely to be Remainers. As
is frequently the case in political arguments, however, the courts
have been called upon to adjudicate. But the real reason for the
fight is not an argument about the finer points of our
constitution. It is whether Parliament should be given the right to
subvert the will of the people in determining the issue of
sovereignty. It is classic Oliver Cromwell stuff. The
Parliamentarians believe that if they win and Parliament must
legislate, then that will effectively put an end to Brexit because
the majority of MPs are in favour of remaining in the EU. The
Brexiteers' concerns are the same. They want the government to
trigger Article 50 under the Royal Prerogative because that way
Parliament will not have a say.
The question for the court is whether any obligations arising
from international law treaties take effect at domestic level until
Parliament chooses to incorporate all or part of the international
law into the domestic sphere, or whether the Royal Prerogative
The Royal Prerogative has always contained powers relating to
foreign affairs. Historically this has involved the making of
treaties at international level. While the Constitutional Reform
and Governance Act 2010 requires that treaties are laid before the
Houses of Parliament for a period of 21 days before they are
ratified, the ability of the Government to ratify treaties remains
a prerogative power, as does the power to amend or withdraw from
The argument on the other side is that there is a wider
constitutional principle which is that it is not open to the
Government to take such a fundamental and irreversible
constitutional step by exercise of the prerogative powers. I
doubt whether the court will agree with this view. The more likely
outcome is that the court will decide that the Government can use
the Royal Prerogative power of foreign affairs to trigger the
Article 50 process. This is because our constitutional arrangements
leave it to the Government to conduct foreign affairs. In this way,
the Government can, and has always been able to, activate Article
50 whenever it likes.
The content of this article is intended to provide a general
guide to the subject matter. Specialist advice should be sought
about your specific circumstances.
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