MPs and peers, including former cabinet ministers, say that with the bill agreed this week and likely to be between £40bn and £50bn, the time has come for the Prime Minister to be completely open on how much Brexit will cost.
Labour is threatening to bring the matter to a head by calling on Tory MPs to back a plan to let the UK’s spending watchdogs assess the financial settlement and give Parliament a vote on it, The Independent can reveal.
It comes 24 hours before Ms May will sit down with European Commission President Jean-Claude Juncker to secure an agreement-in-principle on the withdrawal terms of Brexit – including the divorce bill, Irish border and EU citizens’ rights.
But despite any deal being likely to gain approval at the European Council in mid-December, the British public have not been told by the Government how big the divorce bill is likely to be, or how it is being worked out.
Ex-cabinet minister Michael Heseltine told The Independent: “There is no doubt a lot of people voted for Brexit based on the fantasy that was paraded for them.
“The idea of a great renaissance Britain standing alone in the world has a sort of romantic imagery that can appeal to certain people, as long as you don’t ask the basic facts of who is going to pay for it.
“But I ask the question – what would a Conservative opposition do if a Labour party proposed to spend £30bn, £40bn or £50bn without telling Parliament what it was doing with it?”
His point was underscored by sitting Conservative MPs, such as ex-minister Stephen Hammond, who said: “It is very difficult for the Government to continue to say post-council that we cannot set it out, cannot set out how it is calculated, even as the next stage of negotiations starts – once it is agreed, it is agreed.
“I’m hoping the Government will take a view to keep its promise to be as transparent as possible and we will be able to see exactly what this is.”
He was joined by Heidi Allen MP, who said: “We do need transparency. It should be all out, warts and all. It should be everything – this is what the referendum is costing us in financial terms and deal terms and citizens’ rights terms.
“We need to know all the elements that are changing as a consequence of that vote.”
She added: “I think it’s entirely reasonable and possible to suggest that we will hear what that figure is.”
The issue could come to a head on Wednesday, when Labour tables an amendment to the EU (Withdrawal) Bill going through the Commons.
If passed, it would require any financial settlement to be assessed by both the Office for Budget Responsibility and the National Audit Office to ensure it is a good deal for taxpayers – and it would give Parliament the chance to approve or reject it in a vote.
Shadow Brexit Secretary Sir Keir Starmer said: “Labour has been clear from the outset that any agreement with the EU on money must meet our international obligations while delivering a fair deal for British taxpayers.
“However, it is also essential that the Government is transparent at every stage of this process and Parliament is given sufficient opportunity to scrutinise the final figure.
“That is why on Wednesday we will be urging Tory MPs to back our call for the financial agreement to be independently assessed by the Office for Budget Responsibility and the National Audit Office, and signed off by Parliament.”
The Independent reported earlier this week that British and European Union negotiators had reached a provisional agreement on the “divorce bill” that could see the UK paying some £45bn, though other estimates put the potential sum higher at £55bn or even up to £100bn in the long term.
It was suggested in reports from Brussels that the figure would be deliberately left open to interpretation to give the Prime Minister political cover in the UK.
Liberal Democrat leader Sir Vince Cable said: “The Government must come clean with the British people over the size of the Brexit bill.
“[Brexit Secretary] David Davis used to be a champion of government transparency, now he consistently seems to by trying to hide the true impact of Brexit from the public.
“It’s crucial that once the true cost of Brexit becomes clear, the British people have the chance to reject the final deal and stay in the EU.”
Mr Juncker has said that the meeting with Ms May on 4 December will allow the EU to see whether sufficient progress has been made on withdrawal issues.
If he is satisfied, the commission will recommend to member state leaders at the European Council on 14 December that talks move on to discuss transition and trade.