What Parliament Needs to Do to Change Brexit Date From March 29

(Bloomberg) -- Theresa May returned from the Brussels summit after securing a delay to Brexit of at least two weeks. But the default position in U.K. law remains for Britain to leave the European Union next Friday.

So here's what needs to happen to change the date:

The Law...

Britain's departure is enshrined in the European Union (Withdrawal) Act passed earlier this year. It determines “Exit Day” as March 29, 2019 at 11 p.m. That's midnight in Brussels and two years to the day since Britain signaled in a formal letter its intention to pull out of the bloc.

...And How To Change It

The same act states that a minister may “by regulations” amend that date. That would likely fall to Brexit Secretary Stephen Barclay. He or another government minister lays a piece of secondary legislation, known as a statutory instrument, before Parliament. Rules state that must be done the day before it's voted on, so in theory that's Thursday, March 28 at the latest.

What's The New Exit Date?

Drafting the instrument is complicated by the fact ministers still don't know what day the U.K. will leave the EU. That's because the bloc agreed to delay Brexit until May 22 if May can persuade Parliament to approve the divorce deal next week. If she fails to do so, Britain would only have until April 12 to decide whether to leave without an agreement, or request a much longer extension.

May Says U.K. Could Seek Another Extension Before April 12

“There are obviously two potential dates now going forward, and we'll have to have that discussion with the legislative team as to how best to take the statutory instruments forward,” May's spokesman, James Slack, told reporters Friday.

A Parliamentary vote on the deal next week -- likely on Tuesday or Wednesday, will provide clarity on the new date.

Completing the Change

Once laid, the instrument will then be examined by a committee of lawmakers representative of the House of Commons. Typically there would be nine Conservatives, seven Labour lawmakers and another from a third party. The panel would examine it in a debate that would last no longer than 90 minutes, at the end of which a vote may be held.

The outcome of that vote is not binding, so either way the government would then schedule votes in both the Commons and House of Lords, which must both approve it. Then it can be signed by a minister and become law.

--With assistance from Robert Hutton.

To contact the reporter on this story: Alex Morales in London at amorales2@bloomberg.net

To contact the editors responsible for this story: Tim Ross at tross54@bloomberg.net, Stuart Biggs, Emma Ross-Thomas