The chancellor has hinted at a potential Brexit delay as the Government may "need a little bit more time" to get a deal.
Philip Hammond said: "There's no point just kicking this can down the road, we have to find a solution to the challenge of how we leave the European Union, and if we don't get a deal, the stark choice is between no deal and no Brexit and neither of which is an acceptable outcome.
He added: "But if we do get the deal and we need a little bit more time to put all the legislation and so on in place everybody on both sides will take a reasonable approach to that."
- Mike Thompson of the Association of the British Pharmaceutical Industry tells ITV News Political Correspondent Libby Wiener the risks of Britain not getting a Brexit deal on patients and medicines
Despite the chancellor's comments, Downing Street have said: "We are still leaving the European Union on March 29th and we remain committed to ensuring all the necessary legislation is in place by then.
"It is a challenging timetable but we are making good progress.”
Earlier Liam Fox warned MPs that they may not be re-elected to Parliament if they block Theresa May's Brexit agreement and force the UK to crash out of the EU without a deal.
The international trade secretary said politicians would have "little cover when they next face the voters" if their actions led to a no-deal exit, as he became the latest frontbencher to suggest Britain's withdrawal may have to be delayed.
Mr Fox said Downing Street’s insistence that the UK will leave the EU on March 29, and suggestions by foreign secretary Jeremy Hunt and Commons leader Andrea Leadsom that the exit date could be pushed back were not "incompatible" stances.
"There would be a huge difference between an extension to Article 50 because we hadn't reached an agreement or a short delay because we had reached an agreement and needed the legislation to implement it," he said after a speech in London.
"We can get our domestic legislation through if we quickly reach an agreement with the EU and that’s in everyone's interest."
Dr Fox, a prominent Brexiteer, said he hoped to avoid a no-deal exit by securing an agreement.
But he warned: "I listen to Members of Parliament complaining about the potential effects of no-deal while voting against the deal itself.
"I think they have to ask themselves whose interests they actually represent because ultimately they will have to answer to their voters for their own decisions.
"Those who block the deal and then complain about no-deal I think will have little cover when they next face the voters."
Dr Fox also urged the remaining EU members to reach an agreement with the UK "as quickly as possible", as he said it was "not a good time" to introduce "unnecessary instability" into the European economy.
He told the audience at the Policy Exchange think tank: "We are still aiming to get to the 29th March – that’s the date we promised the British people. The answer is to reach an agreement as quickly as possible. And I think there are factors frankly driving that process.
"Yesterday we saw that Italy is now officially in recession, we’ve seen weakness in the German economy and we've seen weakness in the French economy.
"This is not a good time to introduce further unnecessary instability into that European economy which is why I hope the European Union will recognise that the best way forward for all of us is to get an agreement as quickly as possible."