The UK Independence Party MEP Marta Andreasen has defected to the Conservatives.
She alleges that UKIP leader Nigel Farage "treats any views other than his own with contempt."
She adds: "Essentially, I do not see the party being led to achieve presence in Westminster which is the place where decisions can be made to stop the EU juggernaut."
Ms Andreasen says she was convinced to switch to the Conservatives after David Cameron's "game changer" speech on Britain's relations with Europe, pledging an in-out referendum on the issue.
"I was also reassured by the financial deal that David Cameron got for Britain on the EU Budget", she added.
More top news
Rain will affect northern England and Wales later in the day, particularly over the hills. Elsewhere it will be drier but breezy.
The Chancellor will promise to fix a glitch, which means repayments continue to be taken for up to 12 months after the loan is paid off.
The proposal will see the introduction of a discounted railcard for 26-30-year-olds, as the government looks to lessen the cost of living.