David Davis has been accused of "going weak at the knees" after he told MPs that the UK government would consider giving the EU budget contributions after Brexit.
The secretary for exiting the EU said Britain would deliberate such a move after Labour's Wayne David MP asked if the government would pay for extensive access to parts of the EU's single-market.
"The major criterion here is we get the best possible access for goods and services and if that is included in what he's talking about then we'll consider it," Davis replied.
The Eurosceptic's comments have gone down badly with Ukip's new Brexit spokesman, Gerard Batten MEP. "David is already going weak at the knees. It is ridiculous to offer to pay to trade with the EU. Every country in the world has access to the single market," he said.
"We should take the initiative and offer the EU the choice: do they want continued tariff-free trade with the UK, or do they wish to trade under World Trade Organisation rules and impose the Common External Tariffs on us?"
Batten claimed the latter would impact "far more" on the EU than on the UK and he urged the government to start showing "some guts" in dealing with Brexit.
But the government cannot start negotiations with the EU until Article 50, the official mechanism to break from Brussels, is triggered.
Theresa May has promised to make the move by March 2017, but she was dealt a blow in November when the High Court ruled that MPs must have a vote on the issue.
The government are contesting the decision at the Supreme Court from 5 December, with a final ruling expected in January 2017.
European Council President Donald Tusk, meanwhile, has poured cold water over May's efforts to strike an early deal on the residency rights of EU nationals in the UK and Britons on the continent.
The EU chief stressed that the UK prime minister must trigger Article 50 before formal negotiations can start.