Theresa May has insisted she believes it will be possible to agree the shape of Britain’s new trade relationship with the European Union within the two-year timeframe for Brexit negotiations.

The Prime Minister’s comment came after Germany’s foreign minister Sigmar Gabriel cast doubt on the possibility of completing the “laborious endeavour” in such a short period.

Mr Gabriel instead suggested both sides may have to be content with getting as far as they can within two years, rather than sealing the deal within that timeframe.

Speaking during a visit to Jordan, Mrs May said it was “sensible and pragmatic” to ensure that individuals and businesses have a clear idea of what the future arrangements will be by the time the UK leaves the EU in March 2019.

But she stopped short of claiming that a trade deal could be signed within that time. European Council president Donald Tusk made clear in his draft guidelines for negotiations, released on Friday, that EU rules insist that a deal can be signed only after the UK has left.

Mrs May told Sky News: “There’s obviously a legal situation in terms of how the EU can conduct trade negotiations. I’m clear that by the point at which we leave the EU, it’s right that everybody should know what the future arrangements, the future relationship, that future partnership between us and the European Union will be.”

“That’s the sensible thing, it’s the pragmatic way to look at this, and I believe that’s what we will do.”

Asked if she believed this can be done within two years, she replied: “Yes.”

The influential House of Commons Exiting the EU Committee has called on Mrs May to commission an assessment of the cost of leaving the EU without a trade deal, in a report which said her claim that this scenario would be “better than a bad deal” was “unsubstantiated”.

Responding to the report - which was repudiated by six pro-Brexit members of the committee - Mrs May told Sky: “As I said in the Article 50 letter, I set out what would be a ‘no deal’ situation, but I also said that I don’t think that’s in anybody’s interests.”

“We will be working to get the best possible deal in the British national interest.

“I believe that deal will be good for the European Union as well. I believe both sides will be working to ensure we have a good, positive, deep and special partnership going into the future.”

Germany’s chancellor Angela Merkel and French president Francois Hollande have insisted the terms of the separation - including the so-called “divorce bill” - must be settled before they can move on to discuss a new trade relationship.

That puts them directly at odds with Theresa May, who said in her formal letter notifying Mr Tusk of Britain’s intention to withdraw from the EU under the terms of Article 50 of its treaties that she wanted the two negotiations to proceed in parallel.

In an interview with The Independent, Mr Gabriel said: “We are as keen as the UK is to complete both agreements as soon as possible.

“First, we have to get things right on the orderly withdrawal, then we will want to talk as soon as possible about our future relationship and get as far as we can within the next two years.

“However, I don’t want to speculate on timeframes at a time when negotiations have not even started yet. Both sides must recognise that an agreement on a wide-ranging partnership will be quite a laborious endeavour.”

Liberal Democrat leader Tim Farron said Mr Gabriel’s comments “show a level of awareness that has so far escaped our Government”, adding: “The negotiations ahead are going to be complex and challenging ... we are now starting to see just how many spanners could be thrown in the works to turn this around within two years.”

But Mrs May insisted: “Let’s look at the whole question of where we end up. At the end of this negotiation, will we have looked at both withdrawal and the future relationship? That’s what’s important. That’s what I’m asking for and that’s what I believe increasingly we will see.

“You will see from the European Union, various people have commented that they think we should get on to looking at that future relationship soon, and we will do that.

“What’s important is that when we leave the EU, people know what the future relationship is. It’s common sense, it’s pragmatic for people, it’s pragmatic for businesses, and I believe that’s what we will be working for and it’s what both sides will be working for.”

Defending her decision - interpreted by many in Europe as a threat - to raise the possibility in her Article 50 letter of weakened security co-operation in the case of a failure to reach a trade deal, Mrs May said: “On the security issue, there is a very practical reason for raising it in the letter.

“We are currently a member of certain programmes and certain systems around Europe that help us to co-operate on exchanging information about terrorists, but also about criminals.

“Once we leave the EU our membership of those systems lapses, so it’s right that as part of the negotiations we will be talking to the European Union about how we can continue with those arrangements. It’s in our interests, it’s also in theirs.”

Challenged over whether she took personal responsibility for the terms of the Brexit deal which she has decided to seek, Mrs May said: “The British people chose to leave the European Union. I’ve set out very clearly the European Union has made clear that membership of the single market effectively means membership of the EU.

“People have decided not to be members of the European Union, so our relationship with the single market will be a different one in future, but that doesn’t mean it can’t be a really good trade relationship that will enable our firms to have free access to the single market and continue to trade in the ways that they have done in the past.”