Nigel Farage claimed that Ukip stands a better chance of holding the balance of power at Westminster than the SNP - as he named an immediate European Union referendum as his price for propping up a government.

 

The Ukip leader downplayed the SNP's claims it could decide who enters Downing Street, saying a nationalist surge would fail to increase the overall number of seats held by left-wing parties.

His comments came as he deliberately targeted wavering Labour voters at the launch of Ukip's General Election campaign with an attack on capitalism.

At the event, in a cinema in the once popular seaside resort of Canvey island in the Thames Estuary, he said: "If you look at the SNP vote .. they are taking every one of those seats directly off the Labour party.

"So the arithmetic suggests that whether the SNP win 10, 20 or 40 seats, that potential electoral pact that seems to be on the centre-left of politics does not go up.

"The arithmetic does not change if the SNP win seats.

"The arithmetic changes hugely if Ukip win seats like Heywood and Middleton from the Labour party, seats like Eastleigh from the Liberal Democrats and who know, perhaps even wins seats like Thanet South (where Mr Farage is the candidate) from the Conservative party".

He added: "If Labour and the SNP are there on the left - that does not actually increase the number of seats available on the left".

Despite the rhetoric, which included a prediction that Ukip would "stun" political observers with the number of seats it would take in May, Mr Farage also warned his party they might only make a "massive" breakthrough in British politics at the next general election, due in 2020.

On potential deals, if there is a hung parliament in May he said that the "key issue" for his party was the EU.

"We will only do a deal with anyone on the condition that there is an in/out referendum- on the EU," he said.

He also ruled out a formal coalition and said his party would instead seek an informal alliance on the 'confidence and supply ' model.

The SNP declined to comment on Mr Farage's remarks.

But last month Alex Salmond likened the Ukip leader to a "meteorite" which will soon "crumble to dust".

During an election launch light on new policy announcements, Mr Farage also said Ukip would campaign against both the bedroom tax and the mansion tax which, he said, "further divide a country that is not at ease with itself".

In a full-throated attack he also warned capitalism was currently failing in the UK, in a move designed to appeal to disaffected Labour voters, especially in the north of England.

He also attempted to take on Labour's 'One Nation' slogan, saying Ukip was the only "truly national political party", while the Tories were dismissed as a "regional party for the South of England" and Labour as the same in the North.

He went on to describe his party as "the challenger in virtually every parliamentary seat from Birmingham up to Hadrian's Wall".

"We are going to give Labour in the North of England a real run for their money, that I have no doubt at all," he added.

Mr Farage. known to enjoy a pint and a cigarette, was introduced onstage by Jamie Huntman, Ukip's parliamentary candidate for Castle Point, which includes Canvey Island, as the politician who "refreshed the parts that other politicians cannot reach".

The Ukip leader was, however, shy about revealing how much weight he has lost in his post-Christmas no-alcohol diet.

He did, however, admit he was wearing suits he had not squeezed into for years.

Labour shadow cabinet minister Jon Trickett said Mr Farage had a "long-held belief" in NHS privatisation and tax breaks, adding: "The truth is Ukip are a party of Tory people, Tory policies and Tory money: they are more Tory than the Tories."