Tory and Labour politicians have underestimated the strength of feeling among Brexit voters, Nigel Farage said as the two main parties struggled to respond to the electoral threat he poses.

Mr Farage expects his Brexit Party to “sweep the board” at the May 23 European elections, claiming voters and members were deserting Theresa May and Jeremy Corbyn to back him.

Labour’s deputy leader Tom Watson called for his party to demand a second Brexit referendum rather than “sit on the fence” in response to Mr Farage, while Tory grassroots anger with Mrs May led to members and councillors indicating they will back the Brexit Party rather than Conservative candidates at the European poll.

Mr Farage told the Press Association: “Westminster has just underestimated how the country feels about this.

“They thought they could get away with just kicking the can down the road endlessly, that people would just put up with it.

“I think a lot of people now who did vote Brexit now realise, with this Parliament, unless there is huge pressure put upon them it simply isn’t going to be delivered.”

He claimed the Brexit Party was now “well ahead of 60,000” registered supporters paying £25 each, adding: “I have just had my accountant on saying one is joining every 12 seconds.”

Mr Farage said: “A lot of Conservatives are disgusted with what the party has done.

“But equally, if Tom Watson thinks that the Labour Party going for a second referendum is going to solve everything, I have got news for him because if you go to south Wales or the Midlands or the north of England you find Labour constituencies with big Leave majorities.

“Five million people who voted Brexit also voted for Mr Corbyn in 2017.”

European Parliament elections
Nigel Farage visited the Shoreham Aircraft Museum, where he warned that rival parties had underestimated the strength of feeling among Leave voters (Andrew Matthews/PA)

In an Observer article Mr Watson said: “Labour won’t defeat Farage by being mealy-mouthed and sounding as if we half agree with him.

“We won’t beat him unless we can inspire the millions crying out for a different direction.”

In remarks which appear aimed at putting pressure on Mr Corbyn to make a second referendum a red line issue in Brexit talks with Mrs May, Labour’s deputy leader said a “confirmatory” referendum on any deal was “the very least” that voters should expect.

He said: “We won’t win if we sit on the fence about the most crucial issue that has faced our country for a generation.”

Mr Corbyn insisted Labour was not worried about Mr Farage, dismissing his platform as “simple populism”.

Mr Corbyn told the Sunday Mirror: “Farage just says ‘let’s get out of Europe without a deal’.

“But I do think he has to be challenged. If you just walk away from Europe, the complications are immense.

“There’s a very integrated manufacturing process with us and Europe.

“Many of our factories rely on just-in-time deliveries from Europe and deliver to Europe on a just-in-time basis.

“If that is disrupted there are massive problems.”

Mr Farage dismissed as “scare stories” warnings about the impact of no-deal Brexit on businesses although he acknowledged there could be disruption.

“Even if there was a little bit of short-term disruption, when you move house there is disruption. Change does bring a little bit of disruption,” he said.

“But I think it’s a chance for us to become competitive and reach out to the world. Economically I’m very, very bullish about it.”

An ORB poll for the Sunday Telegraph put the Conservatives three points behind Labour, on 26% compared to the Opposition’s 29%.

The Brexit Party has a 14% share, according to the online poll of 2,107 people.

The momentum generated by Mr Farage’s Brexit Party has sent shockwaves through the Conservative Party.

Some 62% of the 1,132 Tory members surveyed by the ConservativeHome website said they would vote for Mr Farage’s party in the European contest.

And a survey of 781 elected Conservative councillors for The Mail On Sunday found 40% were planning to back the Brexit Party.

Just over half, 52%, said they would vote Tory at the European election, a figure that would rise to 65% if Theresa May was replaced by Brexiteer Boris Johnson, the Survation poll for The Mail On Sunday found.

Some 15% of those surveyed said they believed Mr Farage would be the best leader of the Conservative Party, only Mr Johnson was ahead of him on 19%.