Thousands of Conservative members are likely to defect to a new Brexit party which was officially recognised on Friday by the electoral regulator, its backers claim.

The Electoral Commission on Friday formally recognised the Brexit Party as an official organisation which will allow it to field candidates at elections.

Nigel Farage, the former Ukip leader who is supporting the party, said "the engine is running" and he stood "ready for battle" to fight the Tories and Labour if European Parliament elections are held on May 23.

Political space for a new anti-EU party has been created by the lurch to the right by the UK Independence Party, which has been adopting more strident anti-Muslim policies.

The timing of the official recognition will be a wake-up call to Theresa May, the Prime Minister, of the electoral risk to the Tory party of agreeing a softer Brexit deal over the next few weeks.

A 24-page copy of the Brexit Party's constitution – which has been seen by The Telegraph – makes clear that it is set up to appeal to disaffected Conservatives.

Its main policy is “that the United Kingdom shall cease to be a member of the European Union and shall not thereafter make any treaty or join any international organisation which involves in any way the surrender of any part of the United Kingdom’s sovereignty”.