Government lawyers have warned Theresa May that drawing up a very short piece of legislation in response to Tuesday’s supreme court ruling on whether MPs should be given a vote on Brexit may not be adequate.

The Guardian understands that legal advice to the prime minister and the Brexit secretary, David Davis, suggests that while a single-clause bill would be politically attractive if they lose the case, it could store up difficulties for the government further down the line.

Ministers will only have to put a new Brexit law to a vote of MPs and peers before triggering article 50 if the 11 most senior judges in the country demand it in a much anticipated ruling due at 9.30am on Tuesday morning.

Lawyers representing both sides will be given early sight of the judgment from 8am before the court’s president, Lord Neuberger, reads out the ruling to a packed courtroom. If the government loses the appeal, Davis is expected to make a statement to the Commons at lunchtime, with a bill published later in the week.

Ministers think it is very likely they will be told that MPs must be given a vote on Brexit and have already drawn up a bill to be published quickly after the ruling. Several versions are understood to have been prepared to deal with all the permutations.



Ministers were keen to make the proposed law as short as possible in order to avoid opposition parties being able to heavily amend the legislation and so it can stick to May’s tight timetable for Brexit.

Having promised to start the formal process by the end of March, the ideal formulation from the prime minister’s standpoint would be a single line asking MPs and peers to rubber-stamp the triggering of article 50.

But politicians and strategists have received advice from internal government lawyers who fear that even if the ruling allows a one-line bill, failure to provide enough detail could leave the government vulnerable to further legal appeals in the future.

If the legislation is too short, leading figures in the Labour party would be likely to accuse ministers of being arrogant and wasting time in appealing against the original high court judgment, while the Scottish National party is also concerned.

Gina Miller, the key claimant in the most important constitutional case to ever be heard by the supreme court, said that the government was only facing the challenge because of “how poorly drafted” the original referendum bill had been.

“It would make good legal sense to make sure it is a watertight bill, to avoid loopholes that people can come back on,” she said, arguing that the move towards Brexit was so significant it should be a thorough piece of legislation. “The normal process in parliament would mean a white paper being published,” she said.

She said it was important that the judges were not attacked in the aftermath of their ruling. “I think that, whatever the judgment is, it has to be remembered that the question I asked the courts was a legal question and not political. So it is important for those reporting on it, and responding, to remember not to politicise it. This is a legitimate legal question for the courts.”

Despite Miller’s plea, the ruling will result in a fierce debate within the media and in parliament, with opposition parties lining up to use a government bill to place demands on its Brexit plans.

Jeremy Corbyn’s party will attempt to amend the legislation to make a vote by MPs on the final Brexit deal much more significant, saying that May will have to return to the EU to negotiate a better agreement if they vote against her proposed divorce settlement. Currently, the government is preparing to walk away if parliament rejects the offer.



The Liberal Democrats will be pressing for a referendum on the overall Brexit agreement, while the SNP wants to make sure that Scotland remains a member of the single market.

Nicola Sturgeon’s Scottish government is also part of Tuesday’s supreme court ruling; her party wants MSPs at Holyrood to vote on whether article 50 should be triggered. However, May is not expecting to lose that part of the case.

Jolyon Maugham QC, who is bringing a separate challenge over the reversibility of article 50, said that one legal scenario could involve the supreme court following the suggestion made by its deputy president, Lady Hale, in a speech last year that a “comprehensive replacement for the 1972 [European Communities] Act” would be needed to trigger Brexit.

On that basis, a one-clause bill would not be possible, Maugham said. “It’s not easy to see an interim measure between a one-clause bill and the solution mooted by Lady Hale. It might be the matter of rights being removed by article 50 unless further steps are taken to preserve them explicitly.”

Tim Farron, the Lib Dem leader, said: “The government has done everything possible to avoid proper scrutiny of their plan for Brexit, so it’s no surprise they will be looking to get this through parliament as quickly as possible.

“But rushing to meet an imaginary deadline could be deeply damaging for our negotiating position going forward, and the government should seriously consider allowing proper parliamentary debate before article 50 is officially triggered.”

The lawyers’ advice comes as fresh polling gives the Conservatives a 16-point lead over Labour. The Guardian/ICM poll also delves into public views on Brexit, suggesting that if talks fail to yield an acceptable outcome within the permitted time frame, almost half (49%) of people believe that we should simply leave the EU without a deal, while a third (33%) would want to see a postponement or suspension of Brexit.



However, if the terms of the deal are not considered to be in the UK’s interest, 63% back the idea of leaving without a trade deal, compared with the 8% who would rather accept a bad agreement.

The poll suggests that 26% of voters want a second referendum and that Labour could make gains with a clearer strategy to target remainers by suggesting that the final vote by MPs would hold more sway – in line with the party’s latest plans.

