UKIP launched its election manifesto on Thursday by suggesting Theresa May bears some responsibility for the Manchester terror attack, while pledging a series of policies targeted at reducing immigration.
Policies unveiled in the manifesto include a ban on face coverings in public spaces, a ban on Britons who fight for ISIS returning to the UK, and more police for anti-terror work.
Immigrants would also be forced to pass a values test to ensure they hold the view that women and LGBT people are equal.
UKIP was the first political party to return to national campaigning in the wake of the Manchester terror attack. Suzanne Evans, the party's deputy chair, said the prime minister "must bear some responsibility" for the bombing.
"All politicians who voted against measures or voted for measures to make cuts bear some responsibility," she told reporters in central London. However, she added: "The only person who is responsible, or people who were responsible, for what happened in Manchester are the terrorists, let me make that absolutely clear."
Evans also criticised "left-wing virtue signallers and cowardly politicians who refuse to admit there is a problem with radical Islam in this country" and said UKIP is always willing to say things other parties do not.
Nuttall called for a direct response to the attacks: "It is not the British way to turn a blind eye to evil in our midst – it is not good enough to light candles and proclaim that extremists will not beat us. Action is required on multiple fronts."
He proposed a "more muscular approach to integration and against segregation".
"No doubt we will suffer insults from the politically correct brigade. But that will not deter us," said Nuttall. "Just as we were proved right about the strains of excessive immigration and we were right about how Brussels has hollowed out our democracy, so we will be right about Britain's integration emergency. This party is all about believing in our country and putting Britain first."
The party also pledged to invest billions in the NHS and armed forces, while cutting foreign aid and funding thousands of extra border guards.
Polls suggest UKIP has lost the support of many of the 4 million people who voted for it in the 2015 general election – the party is now as low as 3% in some polls.
Party sources told BuzzFeed News that UKIP insiders know the party is likely to suffer a major hit to its vote share in the forthcoming election and is unlikely to win any seats in parliament. One source said this election was about "staying on the pitch" in the hope that pro-Brexit Conservative voters will ultimately become disillusioned with the terms of May's deal with the EU and return to UKIP over the coming 18 months.
Many journalists who asked questions about the decision to launch the manifesto shortly after the Manchester terror attack were heckled by UKIP supporters in the room – and even some of the party's MEPs.
BBC political editor Laura Kuenssberg was met with cries of "go back down your hole", "don't you understand English", and "what a stupid question" after she asked Nuttall whether he was exploiting the attack.
Earl Dartmouth, a hereditary peer who also serves as a UKIP MEP, told BuzzFeed News he had shouted "go back to school" at the BBC political editor.
"The BBC is fake news," he said. "BuzzFeed isn't fake news but the BBC is fake news. We see it time and time again – they have their own political agenda. That is inappropriate in public service broadcaster which is financed by public subscription. We saw how completely lacking in impartiality the distinguished lady is."