Britain will have to make radically greater payments into the European Union if the country rejoins with the bill potentially hitting £41billion, according to a eurosceptic think tank. The Bow Group has calculated the UK gross contribution could range from £28billion to £41billion – much more than the £14.4billion paid in 2019. This is based on the assumption there is no possibility the EU would agree to restore the permanent “rebate” negotiated by Margaret Thatcher.

Her former aide Lord Redwood, warned: “The UK would need to impose a large new tax; we cannot afford to go in. We would worry markets more with yet more borrowing. The last thing we need is yet more spending and laws from Brussels.”

According to the House of Commons Library, in 2016 – the year Britons voted to leave the EU – the UK made a gross contribution to the EU Budget of £13.1billion and a net contribution of £9.6billion.

Ben Harris-Quinney, who chairs the Bow Group, said: “Despite promises to accept Brexit the Labour party now seems to be set on the path of quietly taking Britain back into the EU. It’s important that the British public understands that doing so would be far more costly than our previous membership, to say nothing of a likely requirement to join the euro, far greater regulation, and further decades of uncontrolled borders.”

Eurosceptics argue the EU wants the UK to return to boost the finances of the bloc. When Czech PM Andrej Babis was asked if would support the return of Britain to the EU, he said: “Yes of course. We need more money.”

Conservative shadow foreign minister Wendy Morton pointed to his words, saying: “Andy Burnham can’t find the cash to fund our defence, yet he seems comfortable with the idea of handing over billions to Brussels. Instead of trying to turn back the clock to 2016, he should focus on a plan for taking the country forward.”

A Reform UK spokesman warned: “Andy Burnham’s plan to reopen the divisions of the Brexit debate will not only betray the 17.4 million people who voted for Brexit, but will also cost this country dearly. Shackling us to a crumbling bloc whose share of the global economy is rapidly declining will be an economic disaster for Britain, forcing us to become a rule-taker yet again and threatening £164billion worth of post-Brexit trade agreements.”

However, a spokesperson for the pro-EU group Best for Britain said it was “unlikely” the UK could not get “some for of rebate”, adding: “It isn’t an accurate calculation of the cost to the taxpayer, and ignores the £92billion GDP growth to our economy that will be gained from EU membership. A gross calculation of what the UK might have to pay as an EU member is like submitting a tax return without any business expenses, or claiming that your turnover is net profit. But voters facing increased living costs, and businesses swamped by red tape, will be relieved to hear that pro-Brexit voices are finally taking the prospect of UK membership of the EU seriously.”

David Campbell Bannerman, a former MEP who served as deputy leader of UKIP insisted that EU re-entry was “totally unaffordable”. He said: “We would be mad to rejoin and anyone trying to rejoin should be prosecuted for misconduct in public office.”

A Government spokesperson said: “These figures are completely speculative. We are building an ambitious, close relationship with the EU that will strengthen our economy and create more opportunities for young people and communities across the whole UK.”