UKIP in Scotland is in "turmoil" after six of its nine European candidates quit amid allegations of dirty tricks and claims an ally of UK leader Nigel Farage was unfairly helped.

The six, who include Scottish leader Lord Christopher Monckton and chairman Mike Scott-Hayward, stood down as ballot papers were about to be sent out.

But the party pushed ahead with the selection and David Coburn, who is Ukip's London chairman, was the controversial winner. A party source described the process as a "shambles".

Some candidates were said to have become concerned about the alleged tactics being used. There was also suspicion about the presence in the race of Mr Coburn, who was believed to be an ally of Mr Farage.

Fears were aggravated when Ukip's Lanarkshire branch sent an email saying it endorsed Mr Coburn and Otto Inglis as "preferred lead and second candidates".

A Ukip spokesman said: "Ukip's candidate list for the European Elections in Scotland has not yet been announced because of a dispute within Ukip Scotland, which has seen some candidates, including the Scottish Leader Lord Monckton, at odds with others."

He added: "The Party's National Executive Committee decided that it would nonetheless proceed with the ballot, which was won by David Coburn."