A UKIP Scotland general election candidate is at the centre of claims he spat at a political rival.

Alan Melville, who is standing in Edinburgh North and Leith, was accused of the behaviour by a Scottish Green.

Melville denied the spitting claim and said he had made a gesture that looked liked spitting.

UKIP is fielding a record number of candidates in Scotland in May, but the party's attempt to connect with voters has been undermined by outbursts from senior figures in the organisation.

David Coburn, UKIP's sole MEP in Scotland, was condemned recently after likening SNP Minister Humza Yousaf to terrorist supporter Abu Hamza.

The MEP's adviser, Robert Malyn, was also criticised after he made a joke about celebrated physicist Stephen Hawking's motor neurone disease.

Melville, a former Tory candidate who defected to UKIP, is under fire for his alleged behaviour last year.

In her blog, Sarah Beattie-Smith, who is standing for the Greens in the same Edinburgh seat, wrote:

"There was no Lib Dem on the panel tonight but we were joined by the UKIP candidate, Alan Melville. His presence surprised me, not because I hadn't expected the party to take part in hustings but because I hadn't previously put a face to a name.

"It was only upon walking into the room on the night that I realised that Alan Melville is the very same guy who, over 10 days in September, swore and spat at me on an almost daily basis as I ran the Green Yes Tardis on Leith Walk."

At a hustings days later, a video of which is online, a member of the audience asked Beattie-Smith if the spitting and swearing allegation was true.

"Yes, is the simple answer," she said.

Melville interjected: "I have never spat at anybody in my life."

He stood up and attempted to show what he had done, which was a mock spitting gesture.

"I never actually spat. I may have sworn."

He then told the audience: "Let's try and keep this on a friendly level."

Melville was born in Edinburgh and is described on the UKIP website as a former student president at Napier University.

He is quoted saying: "Scotland has a proud tradition of education going back to the 12th century. We need to get back to that. We let too many of our people fall by the wayside in the name of 'equality'; people should be encouraged - and have the facilities - to improve their lives".

A UKIP spokesman said: "It seems that a mock spit has created a mock outrage. No, it is not edifying, but nor is the instant run for outrage on the part of the Green candidate."

A Scottish Greens spokesperson said: "We condemn such behaviour and would expect other parties to do likewise. Sadly it's the sort of behaviour that seems to fit Ukip's track record of abusive language."

A spokesman for the Scottish Conservatives said: "These are serious allegations which should be thoroughly checked out by police.

"If true, it will be yet another UKIP embarrassment for a party which has no place or standing in Scotland."