Image copyright PA Image caption United front - UKIP's candidates at the party's Holyrood 2016 manifesto launch at the beginning of April

Ten senior UK Independence Party activists have called for their spokesman in Scotland - David Coburn - to be replaced.

The demand was made in a letter, which has been seen by the BBC, to London-based bosses.

The group believes the party's electoral chances will be damaged if the "gaffe-prone" MEP remains.

David [Coburn] should concentrate on what he does best - charming people and making friends on a one-to-one basis Extract from UKIP activists' letter

Mr Coburn dismissed the criticism as "nonsense" and has received the backing of UKIP leader Nigel Farage.

The party is fielding candidates on the eight regional lists for the Scottish Parliament election on 5 May.

And ahead of the European referendum on 23 June, UKIP in Scotland is also campaigning for the UK to end its membership of the EU.

Mr Coburn is the party's only elected politician in Scotland having won his seat at the Brussels parliament in May 2014.

At the end of February, 10 activists wrote to UKIP's party chairman, Steve Crowther, complaining about "dysfunctional management" in Scotland.

Image copyright PA Image caption David Coburn - an MEP - is Scotland's only elected UKIP politician

They highlighted what they called "major public gaffes" by Mr Coburn and said he was "not suited to being the Scottish face of the Brexit campaign".

The group, including five local party chairmen - Peter Adams, Sarah Devenney, Ross Durrance, Otto Inglis and Bill Wright - demanded that Mr Coburn be replaced.

The letter said: "As we are the only Euro-sceptic party in Scotland, it falls to us to supply an alternative spokesman.

"If the referendum is close failure to do so could cost us our country.

He [David Coburn] just occasionally says things that perhaps he might regret later Nigel Farage, UKIP leader

"We propose that the party conduct tests of our Scottish lead list candidates' abilities in debate and on television generally, and appoint the best performer as our Scottish spokesman.

"Meanwhile, David should concentrate on what he does best - charming people and making friends on a one-to-one basis."

On Twitter, Mr Coburn said those disgruntled with his leadership represented just 1% of the party in Scotland.

He said many of them had now left UKIP and said the fact that none were Holyrood candidates demonstrated the selection process worked "extremely well".

One of those who complained about Mr Coburn, Richard Lucas, tweeted that criticism from five out of eight local party chairmen was "hardly insignificant".

Mr Farage, who is campaigning in Inverness on Wednesday, responded to the criticisms by saying that Mr Coburn was a "highly colourful, larger-than-life" figure.

He added: "He [David Coburn] just occasionally says things that perhaps he might regret later, but you know what, he's come from the world of business, he was dealing in antiques, he's got involved in politics, he's a Scot, he's passionate and he believes in an independent UK.

"Once you rise in the polls and people can see there's a prospect of getting elected to Holyrood, then all sorts of rivalries come into play, we've seen a bit of that in Scotland - it's part of the natural growing pains that political parties have."