A fellow pro-Brexit MEP has criticised Nigel Farage for his "overdramatic" remarks in the EU Parliament on Wednesday (5 March).
The former Ukip leader was met with jeers from other MEPs as he compared the economic and political bloc to the Mafia because of Brussels' £50bn ($62bn) Brexit bill.
"This is overdramatic language," Conservative David Campbell Bannerman told IBTimes UK.
"But the point is that unreasonable demands on the UK from the EU will make it fare more likely that the UK will walk away and set up a World Trade Organisation rules arrangement.
"This will mean the UK leaves sooner, pays less and the EU will face £13bn of tariffs into the EU. The shock could be enough to bring the Euro [currency] down."
Bannerman, who quit Ukip for the Tories in 2011, added: "The EU must not pick macho fights on the edge of its own cliff."
The comments come after the EU Parliament voted 516 to 133 in favour of Guy Verhofstadt's red lines for Brexit negotiations.
The guidelines, from the former Belgium prime minister turned EU Parliament negotiator, insist a transitional deal between the UK and EU cannot exceed three years and that Brussels expects a financial payment as part of the withdrawal agreement.
Shadow Brexit Secretary Sir Keir Starmer said Labour "strongly supports" the parliament's call for a EU-UK deal requiring that Britain retains international standards on human rights, climate change and social rights.
"Labour's six tests for the final Brexit deal made clear that there can be no drop in EU-derived rights and protections," he said.
"These will be the most complex and important negotiations for decades and it is vital that the Prime Minister reflects on these guidelines and sets about building alliances and good faith with our EU partners."