Legal uncertainty hangs over Brexit vote

"This evening's agreement with the European Commission does not contain anything approaching the changes [British prime minister] Theresa May promised parliament and whipped her MPs to vote for," Labour leader Jeremy Corbyn said on Monday.

"It sounds again that nothing has changed," his shadow Brexit minister, Keir Starmer said.

Two MPs from May's ruling Conservative party said the same.

"Seems UK is still permanently locked into the EU, but can 'argue' it can leave. The catch? EU decides if we can leave," Adam Afriyie said.

"We're being played," Sam Gyimah, a former Tory minister said.

Nigel Farage, the EU-phobic British MEP for the UK Independence Party, was the most outspoken. "Nothing has changed. Reject. Reject. Reject," he said.

Meanwhile, the so-called Independent Group of ex-Labour and ex-Tory MPs said Brexit ought to be delayed in order to hold a second referendum.

Dominic Grieve, Britain's former attorney general, echoed their position.

"The proper thing to do is to put it back to the public in a people's vote, in a second referendum," he said on Monday.

Afriyie's comment on being "locked into the EU" referred to the so-called 'backstop' - the previous deal that the UK would remain in the EU customs union until it found a mutually acceptable way to avoid a hard border on the island of Ireland.

The backstop prompted a historic majority of 230 MPs to reject the withdrawal deal in January, raising the prospect of a no-deal Brexit on 29 March.

But EU commission president Jean-Claude Juncker and British prime minister Theresa May agreed three new documents at a meeting in Strasbourg, France, late on Monday designed to assuage those fears.

The first one said the UK could start a dispute in an arbitration court to quit the backstop if the EU did not want to let it out.

The second one said the EU and UK would try to find alternative arrangements to the backstop by the end of 2020.

The third one was a unilateral British declaration in which the UK said it could quit the backstop if the talks on alternative arrangements broke down.

Both May and Juncker were emphatic in saying that the tweaks gave the UK the "legally binding" guarantees it needed to avoid being locked in to EU customs rules.

"It [the backstop] would never be a trap, if either side were to act in bad faith, there is a legal way for either side to exit," Juncker said.

The Irish leader had been informed of the details and had backed the latest accord, Juncker added.

"MPs were clear that legal changes were needed to the backstop. Today we have secured legal changes," May said.

The British attorney general, Geoffrey Cox, is to spend Tuesday morning poring over the details of the new texts.

He will then tell parliament whether he agrees with May's interpretation in an opinion that could swing the vote either way when MPs begin casting their ballots at 7PM British time.

Small print

The European Research Group (ERG) - a clique of hardline Brexiteer MPs in May's party - said they would wait and see what both Cox and their own lawyers made of the EU small print.

"I look forward to the full text and the opinion of the team of lawyers we have set up to advise us," ERG member Steve Baker said.

The head of the Democratic Unionist Party from Northern Ireland was also in wait-and-see mode.

"These publications need careful analysis. We will be taking appropriate advice, scrutinising the text line by line and forming our own judgement," DUP leader Arlene Foster said.

If the deal is rejected by a small margin, May is expected to call another vote prior to 29 March.

If it is rejected by more than 50 votes, MPs are to hold subsequent votes on Wednesday and Thursday on whether to go for a no-deal Brexit or to delay the exit date pending further talks.

For his part, Juncker was clear that the EU was not prepared to go further, however.

"There will be no third chance ... It is this deal or Brexit might not happen at all," he said on Monday.

Damage done

The value of the British pound rose in trading on Asian markets at the same time in a sign of optimism on a breakthrough.

But a report by New Financial, a think-tank in London, said damage to British interests has already been done no matter what the outcome, as financial firms shift staff and assets to other EU capitals.

Its "conservative estimate" was that firms had already moved around €1 trillion in assets and were moving around 5,000 staff out of Britain.

Dublin was the biggest beneficiary with some 100 corporate relocations, followed by Luxembourg (60), Paris (41), Frankfurt (40) and Amsterdam (32), it said.