Media playback is unsupported on your device Media caption Elmar Brock: "They have no idea of their plan"

UK ministers handling Brexit have "no idea of their plan", the chairman of the European Parliament's foreign affairs committee has said.

German MEP Elmar Brok told the BBC that "reality" had "not arrived" in London and a "realistic plan" was needed.

It was wrong to think the UK could stay in the single market without "minimum" commitment to its funding, he said.

The government is working out its negotiating position before full Brexit talks begin next year.

Prime Minister Theresa May has promised to trigger Article 50 of the Lisbon Treaty, starting the full process of leaving the EU, by the end of March.

Talks will then last up to two years, with the government saying on Tuesday that it was "very likely" Parliament would get a vote on the final deal reached.

Last week Foreign Secretary Boris Johnson, one of the leading voices of the Leave campaign, which won June's referendum on EU membership, predicted that the UK would arrange a trade deal "possibly of greater value" than it currently has as part of the single market.

He told MPs it would also be possible to keep "control of our borders" and save "a fair bit of cash".

Mr Brok, an MEP for German Chancellor Angela Merkel's Christian Democrat party, told the BBC: "I've met Boris Johnson for two hours' meetings privately. We've known each other for more than 25 years and these are interesting debates on Brexit."

Two other prominent Leave campaigners, Brexit Secretary David Davis and International Trade Secretary Liam Fox, have been tasked, along with Mr Johnson, with overseeing the process of exiting the EU.

Speaking in London, Mr Brok added: "I'm astonished what they (pro-Brexit ministers) think about the European Union, what they know about the European Union and which conditions have to be fulfilled to come to a deal.

"I've sometimes a feeling that after all this happiness after Brexit, the reality has not arrived in this city - what are the real conditions for coming to a deal and all the technical implications that have to go through?"

Mr Brok said: "I have no clear idea of their plan because they have no idea of their plan. I have not the impression that they know where they want to go and I have also the feeling that they do not know certain conditions which you have to know in order to make a realistic plan."

He added: "They believe, for example, that you can play a part in the single market without financing structure funds."

That would mean "the minimum of conditions" for staying in the single market were "not fulfilled", Mr Brok added.

Mr Fox has described Brexit as a "golden opportunity", urging UK to "rise to the challenge", while Mr Davis has said he will negotiate for continuing tariff-free access to the single market, arguing that this "is in the interest of the other members of the EU as well as us".