Ukip leader Nigel Farage says that if accusations over expenses claims levelled at Janice Atkinson are upheld, she should quit immediately.

His comments come at the end of a turbulent week for the party leader, who was reportedly chased from a pub in his home village of Downe where he was having lunch with his family.

Mr Farage was ambushed by a group of anti-Ukip protestors at the pub, prompting him to label them scum.

Mrs Atkinson, who is the party's candidate in Folkestone and Hythe and MEP for the South East, faces a party disciplinary hearing on Monday.

She was suspended from the party this week after a claim in The Sun newspaper about a lunch costing £950 she hosted at The Hoy bar and restaurant in Margate. It took place during the party’s spring conference in the town.

The Sun filmed a staff member of Atkinson’s team asking for an invoice for £3,150 at the restaurant the next day.

"I have been utterly ruthless with people who have stepped over the line. We are very, very good at weeding this stuff out..." - Nigel Farage

It appeared to suggest the MEP's chief of staff Christine Hewitt had asked for an invoice for a much higher sum than the bill she had originally received.

In secretly filmed footage with the pub landlord, she is heard to say: "The idea is we overcharge them slightly, because that's the way we repatriate it."

The revelations triggered the suspension of Janice Atkinson and a police inquiry into possible fraud.

Mr Farage said that Mrs Atkinson would have to go if the claims are upheld.

Appearing on the Andrew Marr Show, he was asked whether the MEP should stand down if the allegations were proved.

He replied: 'Without a shadow of a doubt."

He defended the party's track record on dealing with members who had transgressed, saying: "I have been utterly ruthless with people who have stepped over the line. We are very, very good at weeding this stuff out."

He also predicted that despite the difficulties Ukip had over candidates, he would win in Thanet South.

Meanwhile, a Conservative candidate in Thanet has denied playing a role in setting up a sting on Atkinson.

Paul Messenger, who is standing for election in the May council poll for the party, said he was a long-standing friend of Dave Goulding, the landlord of the Hoy pub, and offered him advice about what he might do with information concerning the alleged expenses fraud.

However, he had done so as a friend and denied having an active role in setting up the sting conducted by The Sun newspaper.

He said: "Dave is a long-standing friend of mine and confided in me about the e-mails he had received [from Janice Atkinson's office].

"He said he didn't know what to do. I said he had to do what he felt was right. Because I am standing for election, I said I could not get involved because it would look like a political thing.

"I did say I could help get you telephone numbers for national newspapers. I told him that what he had could be political dynamite. He did it because he felt it was the right thing to do."