Theresa May has admitted that EU leaders will seek to punish Britain in the Brexit talks to stop the break-up of the bloc.

The Prime Minister acknowledged that “things will be said” in the negotiations, because of a determination to prevent other countries being tempted to copy the exit vote.

“They don’t want to see others looking to break away and to vote to leave in the way the UK has done,” she said in a newspaper interview.

It is the closest Ms May has come to admitting that Britain will not be able to “have its cake and eat it” – in Boris Johnson’s celebrated and much-mocked phrase.

The comment follows numerous EU leaders insisting they will not allow Britain to break away with a better deal than it currently enjoys as a member.

In particular, they have slapped down any suggestion that both single-market membership and curbs on the free movement of EU people will be offered.

This week, German Chancellor Angela Merkel made clear the UK will not be allowed to "cherry pick" from the four freedoms - including freedom of movement - required for single market membership.

Speaking to the Financial Times, Ms May tried to prepare the ground for the tough talks to come, after several of her own backbenchers crowed that Britain will hold the whip hand.

However, she played down suggestions that Ms Merkel alone, as the leader of the EU’s most economically powerful country, holds the key to the kind of Brexit Britain will get.

She said: “I think it's also important to build a relationship with others sitting around the European table. There are 27 member states which will be negotiating.”

And she added: “What I've been saying to people is I want to see as smooth and orderly a process as possible.

“Of course, it's going to be complex because there's a lot to deal with. You're not a member of something for 40-odd years and then it's easy.”

Some MPs have urged Ms May to delay the triggering of the Article 50 exit clause which will kick-start the two-year withdrawal talks – until the end of 2017, after elections in Germany and France.

But the Prime Minister said: “It's important that we don't leave it for too long, otherwise people will lose faith in their politicians. They'll think that we're trying to pull the wool over their eyes.”

Ms May also said she had tried to encourage a “much more open and free discussion" about policy among Cabinet ministers, in a far formal way than her predecessor David Cameron.

And, after accusations that being photographed in £1,000 leather trousers made her look out of touch, she insisted she was not bothered by commentary about her clothes.

"Do I worry about people focusing on what I wear? No," the Prime Minister said.

“There's a story that might illustrate why. A few years ago I got into a lift in the House of Commons with a young woman who happened to be wearing a nice pair of shoes and I said: 'Oh, nice shoes.' And she said she liked my shoes as well. And then she looked at me and said: 'Your shoes got me into politics'.

The interview also notes that Ms May has a verbatim account of the words she uttered on July 13, as she entered No 10 for the first time, hung on the wall of her office waiting room.