Jeremy Hunt has said Brexit could be delayed as the government may need “extra time” to pass key legislation if Theresa May can agree a deal at the eleventh hour.

The foreign secretary admitted that a technical delay to the Article 50 process could be necessary to prepare for Britain’s exit from the EU, which is legally due to take place on 29 March.

MPs ordered the prime minister to go back to Brussels to renegotiate a key part of her Brexit deal after her plan was resoundingly defeated in the Commons earlier this month.

But despite the Tory truce, Ms May faces an uphill battle to convince the EU to reopen talks on the withdrawal agreement, with European leaders lining up to rebuff her efforts.

Asked about Britain’s exit date, Mr Hunt told the Today programme: “I think that depends on how long this process takes.

“I think it is true that if we ended up approving a deal in the days before 29 March then we might need some extra time to pass critical legislation. But if we are able to make progress sooner, then that might not be necessary.

“We can’t know at this stage exactly which of those scenarios would happen.”

There is growing concern among ministers that there is not enough time to pass the necessary legislation before exit day, amid reports that the February recess could be cancelled to give Ms May more time to win over the EU.

Mr Hunt said a solution had “not been properly worked up” to replace the Irish backstop – which aims to prevent a hard border on the island of Ireland. MPs backed a bid to replace it with “alternative arrangements” in a series of crunch votes on Tuesday.

He said it was “difficult to know” if negotiations would run to the end of March, but added: “Whereas a week ago none of us really knew whether this was going to be possible, we are now in a situation where it clearly is possible.

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“There are lots and lots of hurdles – no one is saying this isn’t going to be very challenging – but we do now have a consensus in parliament.

“We can use that consensus, providing we can meet these concerns – very reasonable concerns – from our friends in Ireland about not having a hard border [and] concerns in the EU about access to the single market.

“Providing we can do that, which I think we can, then I think there is a way through.”

However his Austrian counterpart, Karin Kneissl, said it would be “very difficult” for the Brexit timeframe to be extended and warned that Britain could be heading for a no-deal exit.

She said: “According to the Article 50 procedures, the deadline is 29 March, so there is a time pressure because what couldn’t be reached by negotiation over the last years, it’s very difficult to imagine that there can be a tremendous breakthrough – a magic solution – in the next few days in order also to have this ratified in due time for the remaining EU members.”

Police separate clashing Brexit protesters outside Parliament Show all 11 1 /11 Police separate clashing Brexit protesters outside Parliament Police separate clashing Brexit protesters outside Parliament Anti-Brexit protester Steve Bray (left) and a pro-Brexit protester argue as they demonstrate outside the Houses of Parliament Getty Images Police separate clashing Brexit protesters outside Parliament A pro-Brexit protester argues Getty Images Police separate clashing Brexit protesters outside Parliament Police surround the pro-Brexit protester after he confronted Steve Bray, a pro-European protester Getty Images Police separate clashing Brexit protesters outside Parliament A leave supporter is spoken to by a police officer as he argues with a remain supporter, Steve Bray, outside Parliament PA Police separate clashing Brexit protesters outside Parliament MPs in Parliament are to vote on Theresa May's Brexit deal next week after her December vote was called off in the face of a major defeat Getty Images Police separate clashing Brexit protesters outside Parliament A leave supporter is spoken to by a police officer PA Police separate clashing Brexit protesters outside Parliament Police look on as anti-Brexit protesters demonstrate outside the Houses of Parliament. Getty Images Police separate clashing Brexit protesters outside Parliament Police hold back a leave supporter PA Police separate clashing Brexit protesters outside Parliament A police officer speaks with anti-Brexit protester Steve Bray Getty Images Police separate clashing Brexit protesters outside Parliament Police surround a pro-Brexit protester after he confronted a pro-European protester Getty Images Police separate clashing Brexit protesters outside Parliament Conservative MP David Davies, wearing a gopro camera, speaks to anti-Brexit protester Steve Bray Getty Images

Elsewhere, the Institute for Government think tank said the UK was unprepared for a no-deal Brexit and warned that there could be “extremely damaging” disruption in vital policy areas such as health and borders.

IFG director Bronwen Maddox told the BBC: “The UK is not ready for no deal.