Nigel Farage says he expects Scotland Yard to be called in after claiming a concerted operation by Tory high command - “bordering on corruption” - was instigated to offer jobs and peerages to Brexit Party candidates in return for them standing down from the General Election.

The Brexit Party leader described it as “full-on Venezuelan-style corruption” initiated, allegedly, as the Thursday 4pm deadline to finalise election candidates counted down.

Last night, Richard Tice, the party Chairman, said: “We are proud and grateful that our candidates have resisted these distasteful overtures and stood firm."

Mr Farage, who earlier in the week made a major concession to Boris Johnson by standing down his party’s candidates in 317 Tory-held seats, came under intense pressure to go further and withdraw others in marginals to give more pro-Leave Conservatives a chance of winning against their Labour opponents. However, he resisted.

The anti-EU MEP claimed “many thousands” of phone calls and messages had been made to the party’s remaining 300 candidates urging them to quit in the hours before the nominations’ deadline closed.

Three candidates were said to have withdrawn, including Rupert Lowe, who announced he would not contest Dudley North as the deadline passed. The MEP made clear he had not been offered a peerage.

An indignant Mr Farage declared: “Even Boris Johnson’s Chief Strategic Adviser Sir Edward Lister is calling our candidates and offering them jobs if they withdraw. The system is corrupt and broken."

He made clear he did not think the Prime Minister was personally involved but, rather, figures "who work deep inside No 10 Downing St".

The party leader said: “Today has been an industrial-scale attempt to stop free and open politics happening in our country. No 10 has been directly involved and many thousands of activists all over the country [have been phoning] in a concerted way. Some of the phone calls are nice; some are less than nice. Lots and lots of job offers; jobs on the negotiating team.

"I expect there will be police investigations into what has gone on here," insisted Mr Farage. “The offer of peerages for material return is clearly an offence. This may unravel over the next couple of days."

In a video posted on Twitter, he said Conservative figures had “tried something that frankly is bordering on corruption but it says so much about Westminster and the way things run”.

The party leader alleged that he and eight "senior figures" in his party were offered peerages.

He went on: "I'm not for sale, I'm not interested, I don't want anything. I just want to get Brexit delivered."

No 10 swiftly denied his claims, insisting: “No jobs or peerages have been offered.”

A Conservative spokesman responded by saying: "Neither the Conservative Party nor its officials have offered Brexit Party candidates jobs or peerages. We don't do electoral pacts; our pact is with the British people.

"The only way to get Brexit done and unleash Britain's potential is to vote for your local Conservative candidate, otherwise the country runs the risk of another deadlocked Parliament or even worse a Labour/SNP coalition led by Jeremy Corbyn who would subject Britain to two referendums in 2020."

Last night, one senior Tory source remarked: "Nigel can't deliver Brexit but he could end up blocking it. His outburst is a result of this fact dawning on him."

But Ann Widdecombe, the Brexit Party’s candidate in Plymouth Sutton, revealed that she had received two phone calls from 10 Downing St urging her to quit,

“I don't know about offers but they have been on at me to stand down and talking a lot of rot. They have not offered me a peerage. They have been ringing up putting huge pressure on me," said the former Conservative minister.

Ian Lavery, the Labour Chairman, commented: “It looks like Boris Johnson is trying to stitch-up this election by offering jobs to Brexit party candidates to get them to stand down.

"This gives a whiff of the corrupt way the Establishment works. We can’t allow the Tories to run the country a minute longer. It’s time for real change.”

Nominations for all 650 constituencies had to be submitted by the 4pm deadline. In an unusual move, the Lib Dems, Plaid Cymru and the Greens have announced a Remain alliance pact, whereby the three parties divided up 60 constituencies to try to maximise the anti-Brexit vote in the seats.

The Brexit Party, meantime, announced it would be fielding "around 300" candidates in the national poll. The Green Party said it was standing 500 candidates, 47 more than in 2017, while in Northern Ireland the Democratic Unionists said it would field 17 candidates across the province’s 18 constituencies.

Meanwhile on the campaign trail, Mr Johnson appeared to row back from a promise to cut immigration if the Tories won power on December 12.

The PM said the Conservatives' promised points-based immigration system "may" mean the numbers would come down "in some sectors".

Yet earlier Priti Patel, the Home Secretary, made clear a Tory government would "reduce immigration overall".

At the same time ministers said they were finally abandoning the party's long-standing commitment to get net migration down below 100,000 a year; a target they have never met.

During a visit to a school in Kingston in outer London, Ms Patel conspicuously declined to repeat the commitment to reducing the overall numbers.

"We're at early stages right now," she declared, adding: "Because we're in the middle of an election campaign as well, there's very, very limited things that I can say about the policy development."

And campaigning in Bristol, Mr Johnson also avoided any commitment to an overall cut, saying: "We want to have a controlled system and, yes, that may mean in some sectors immigration comes down."

Earlier, Jeremy Corbyn refused to say if he wanted the number of immigrants coming to the UK to rise or fall, stressing in a BBC interview: “Putting arbitrary figures on it as successive governments have done simply doesn't work."