Theresa May has been put on notice by hardline Conservative Eurosceptics that they could be prepared to vote against her final Brexit deal if the UK continues to pay the £50bn divorce bill for years to come or does not get good trade terms.

A group of Tory MPs are unhappy about the scale of the proposed sum and believe leaving on World Trade Organisation terms would be better, meaning the prime minister might have to rely on Labour support to get parliament’s approval for a final deal before March 2019.

One Tory MP said some members of the Brexit-supporting European Research Group were demanding a meeting with Julian Smith, the new chief whip, to make clear their unhappiness about the idea of phased payments lasting many years.



Brexiters nowhere to be seen as UK raises white flag over EU divorce bill Read more

Other backbenchers are uneasy about the overall amount of money that the UK will pay, although their decision on the vote would depend on whether ministers manage to achieve a good trade agreement with the EU.



Pro-leave cabinet ministers including Boris Johnson and Michael Gove have given the prime minister their backing over the bill, but also continue to insist it is conditional on Britain securing a good final trade agreement. Speaking from Ivory Coast, Johnson signalled he approved of May’s efforts to break the deadlock with the EU over money, saying: “Now’s the time to get the ship off the rocks.”

Peter Bone, the Conservative MP for Wellingborough, told the Guardian he would be prepared to vote down a final Brexit deal that came at too high a price.

“I think people in the country will be very, very upset. I don’t think paying billions to the EU is what the people voted for. Giving billions to the EU is completely the reverse of what people voted for. If the deal is voted down we come out on World Trade Organisation rules. I don’t think that is a problem at all. Then all that money – £60bn lying around – we could use that to help the NHS and other things and even do tax cuts.”

The prime minister was publicly supported by the bulk of senior backbench figures from the former leave campaigns. But former Tory leader Iain Duncan Smith made it clear their support was contingent on satisfactory trade terms in subsequent rounds of negotiation with the European Union.



Duncan Smith told the BBC: “It is also absolutely hinged on a free trade arrangement. If there is no trade deal, then my view – and I would think the whole of the party’s view – would be we don’t owe them any money at all. Because if we don’t have that arrangement, than that whole figure that is being bandied around becomes null and void.”

The chief secretary to the Treasury, Liz Truss insisted in the House of Commons that “nothing is agreed until everything is agreed”. “Any settlement we make is contingent on us securing a suitable outcome as set out in the prime minister’s Florence speech,” she said.



The situation raises the prospect that pro-EU opposition MPs and hardline eurosceptics could at some point all find themselves voting against any deal struck by May with the EU. John Major’s government suffered a series of parliamentary defeats in the 1990s as he struggled to persuade MPs to ratify the EU’s Maastricht Treaty, when eurosceptic Tory rebels allied with Labour to reject key aspects of the legislation.

No 10 has not confirmed how much May is offering the EU to settle the UK’s accounts but officials have not denied the reported figure of around £50bn, with the terms likely to be formally tabled on Monday.



However, she faced ridicule from remain-supporting MPs arguing that she was paying for a worse deal than the UK would get by staying in the EU and anger from some on the Conservative right, who believe Britain should pay nothing at all.

A number of backbench Tories even publicly floated the idea that they could vote against a final Brexit deal if the cost of the divorce bill is too high when the total sum and terms of any trade arrangements are known.

Andrew Bridgen, the Conservative MP for North West Leicestershire, also said it was “of course” a possibility that he and other Brexit supporters could vote against a final deal if the financial terms were not good enough but it was too early to tell without knowing what it will look like.

Key dates before EU summit decides on Brexit progress Read more

“I think it’s fair to say colleagues on the Conservative benches would rather have a clean break than staged payments. But we don’t know. If we said we’d pay you all in one sum and a bit less, they wouldn’t take it? We need to see the whole deal in the round, and the ultimate sanction is no deal is better than a bad deal.”

Other Conservatives who have questioned the size of the divorce bill include Jacob Rees-Mogg, the Conservative MP and darling of the right of the party, and Rob Halfon, the former deputy chair of the party.



Halfon told the Commons on Wednesday: “Given the need for good housekeeping and the pressures on public spending, if the impression is given that we have wads of cash when it comes to Europe, that undermines our arguments on the public sector and on the need for good housekeeping, especially since the House of Lords says that we have no legal financial obligations.

“Does [the minister] not also agree that this is not a divorce bill? We are leaving a club, and once someone leaves a club, they no longer have to pay subscriptions.”

Rees-Mogg said Britain seemed to be “dancing to the tune” of the EU and sought assurances that no payments would be made unless there was a full agreement on trade.

A source close to the Department for Exiting the EU said it had still not been decided whether any payments to the bloc would be made as a lump sum or over many years, as obligations such as pensions commitments become clear.

Brussels sources rejected any linkage between the Brexit bill and the final trade deal, suggesting the UK will be disappointed in the belief that it will only have to pay the money if the trade terms are good enough. One senior insider said: “We don’t accept that logic: this is part of the withdrawal treaty and that will be voted on by the UK parliament and by the European parliament. We’re not going to reopen that. We need to close this.” The source added, “for us, we don’t link them”.