Paul Nuttall says Ukip is 'more important than ever' ahead of the General election
The party, which is the first to begin campaigning in the wake of the Manchester bombing, will launch its manifesto at a Westminster press conference this morning shortly before a national minute's silence to commemorate the victims of Monday's attack.
Mr Nuttall defended the move, saying the best way to fight against terror was "to get back in the saddle" by continuing the election campaign.
Asked whether Ukip was merely a pressure group, he told Radio 4's Today programme: "The referendum was great.
Andrew Neil interview with UKIP CANCELLED after Manchester bombing
UK election: Ukip to launch manifesto for General Election
We won the war and now we have got to win the peace
"We won the war and now we have got to win the peace.
"Theresa May is going to go into these negotiations. I think she will begin to barter things away, I think fisheries will go, I think there will be a deal over freedom of movement of people, I think we will end up paying some sort of divorce bill.
"That isn't what people voted for on June 23 and that's why Ukip needs to stay on the pitch to be the guard dogs of Brexit."
Ukip will be the first party to begin campaigning after the Manchester bombing
He went on: "What we need to do is to ensure that the Prime Minister goes into these negotiations, confident in our great country and in the knowledge that if she begins to backslide that there is a party there that will rise in the polls, that will do well in local elections, that will put the pressure on and that's why Ukip is so important.
"In fact, Ukip is more important now than it has ever been because Ukip is the insurance policy for the country to ensure that we get the Brexit that people voted for last year."
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Nuttall has denied Ukip was a racist party
All the pictures from Stoke Central by-election
Thu, February 23, 2017
Voting has begun in the Stoke-On-Trent Central by-election which was called after sitting Labour MP Tristram Hunt resigned from his seat to be a museum director. The seat has always been a Labour stronghold but will see fierce competition from UKIP as they target people who voted for Brexit and the tradtional Labour working classes
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Labour candidate Gareth Snell celebrates with his wife Sophia (right) after winning the Stoke-on-Trent Central by-election
It came after party activists told the programme that Mr Nuttall should resign, with Ukip candidate for Rotherham Allen Cowles saying the leader had "only added to the chaos".
Responding to the claims, Mr Nuttall said: "I don't agree with that. Don't forget, I mean I was elected as leader of Ukip only six months ago and I was elected with the biggest mandate the party has ever given anyone."
He outlined commitments to cutting foreign aid and cutting immigration but denied that his party was racist.