THERESA May’s plan for Britain to have temporary membership of the European customs union post Brexit has been branded “nonsensical and ridiculous” by Nicola Sturgeon.

David Davis, the Brexit Secretary, took to the airwaves yesterday, promoting the Prime Minister’s proposal for the UK to have an interim agreement on membership of the customs union for up to three years while having the ability to negotiate its own trade deals with other countries; something impossible for members of the customs union, who operate as a bloc.

He hinted that Britain might be willing to pay a fee to Brussels for the privilege of seeking to negotiate its own trade deals with other countries like the USA, China and Australia while effectively being a member of the customs union; something critics labelled as “having your cake and eating it”.

Asked whether Britain would have to pay to stay in the customs union, he said: "Well, what happens in that sort of interim period you will have to leave me to negotiate, I'm afraid; how we do it. But the aim is to bring to an end these huge £10 billion-a-year payments, bring that to an end now.

"We are still haggling with them over what we may owe them in the short term but we are going to bring the overall thing to an end. This is something that is in both sides' interest," said the Secretary of State.

The UK Government has put forward two options on potential post Brexit customs arrangements: one, admitted as “untested”, would see Britain’s system aligned precisely with the EU’s, removing the need for any customs checks at the border; the other would involve the use of technology to create a more efficient system of “highly streamlined” border checks to minimise disruption at ports and airports.

This could involve using number plate recognition technology, which could be linked to customs declarations for what the vehicles were carrying, meaning they would not have to be manually stopped and checked.

The so-called “partnership paper” also suggested if no deal were done, then EU imports to the UK would face import duties and VAT with the prospect of pushing up the cost of such goods to British consumers.

But Mr Davis insisted the negotiations – due to resume at the end of the month - were going "fine" and EU leaders were less hostile than they had been previously.

"The simple truth is we want to come out of this better but they want to come out of it better too. There was a terror early on that we would be the first of many countries breaking off.

"After the victory of[President]Macron in France, that terror is reduced. They are no longer quite so afraid so the punishment battalion side is now reducing," he added.

But the First Minister claimed the Prime Minister’s “have cake and eat it” approach to Brexit was “daft”.

She told BBC Scotland: “You've got the UK Government appearing to say that they don't want to say in 'the' customs union but they want to stay in 'a' customs union, which would be pretty much identical to the European customs union that we're in already. It's nonsensical and ridiculous.

"It increasingly makes the UK Government look like a bit of a laughing stock,” she declared.

Ms Sturgeon added: "I wish we weren't leaving the EU but if the UK is leaving the EU, then the common sense thing to do is to stay in the single market and to stay in the customs union because that will mean we can continue to export goods and services and continue to travel freely like we can today."

Labour’s Sir Keir Starmer, the Shadow Brexit Secretary, said the Government's proposals were "ambiguous, unachievable and offer no viable solutions" with both options on the table likely to lead to delays and extra costs for British firms.

Meantime, his colleague Bill Esterson, the Shadow Trade minister, was accused of “chaos” on Labour’s policy on the customs with Tory HQ saying he was asked 11 times during a radio interview to set it out but failed each time.

"This is one of the biggest issues that our country faces and Labour just don't have a clue,” claimed Conservative backbencher Maria Caulfield.