Media playback is unsupported on your device Media caption Nigel Farage says UKIP are the "form horses" when it comes to migration

Nigel Farage has accused the official EU leave campaign of not focusing hard enough on immigration.

The UKIP leader said Vote Leave had been "too defensive" and needed to speak about the EU's "open borders" to take the fight to the "enemy".

He said the Cabinet ministers in Vote Leave lacked credibility because of the government's record on immigration.

Mr Farage is not part of Vote Leave and is running his own UKIP campaign for an exit vote in 23 June's referendum.

In a speech in Westminster, he said Vote Leave - a cross party campaign headed by Conservative ministers Boris Johnson and Michael Gove - had spent too much time "defending their own goal" from their opponents' economic attacks.

'Remorseless torrent'

He urged them to "get onto the other side of the pitch" and start making a more assertive case over immigration.

He said: "Where the enemy are at their absolute weakest is on this whole question of open door migration, the effect that it's had on the lives of ordinary Britons over the course of the last decade and the threat that it poses given the new terror and security threat that we face in the west.

"I'm sorry to say that at the moment they don't appear to have done it."

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He accused the Remain campaign of a "remorseless torrent of propaganda", attacking the OECD and the International Monetary Fund as "overpaid useless people" and President Obama of "parroting the Number 10 line" after he spoke out against a UK exit.

Raising the New Year's Eve sex attacks in Cologne and warnings of extremists "posing as migrants", he said migration, terror and the security threat was the "weakest" point for the Remain campaign.

'Credible voice'

UKIP-backed Grassroots Out missed out on being designated as the official Leave campaign when the Electoral Commission instead chose Vote Leave after a bitter battle between the rival Brexit camps.

Mr Farage said Vote Leave did not have the "credible voice" to speak out on migration, given the government's attempts to reduce the overall numbers.

He said he had reached out to Vote Leave, saying "let bygones be bygones", but "every time I try to work with them I am rebuffed and rejected". Fine, he added, "we will make the arguments ourselves".

He also said the referendum result would be decided by the level of turnout and the Leave side must "motivate" its supporters to get out and vote on 23 June.

A Vote Leave spokesman said "we wish Nigel well" and insisted the campaign group was committed to creating a "fairer and more humane" immigration system outside the EU.

Earlier this week Home Secretary Theresa May said EU membership made the UK "more secure from crime and terrorism".

'Plain silly'

On security, she said EU membership enabled the UK to access EU-wide information, such as criminal records, to allow the UK to turn away serious criminals and terrorists at the border, fast-track the extradition of offenders and simplify the deportation of prisoners.

She also said the free movement of workers within the EU makes it more difficult to curb immigration to the UK.

Mr Farage seized on this comment in his speech, brandishing a UK passport which he said made it "impossible" to control the numbers arriving, claiming wealthy people living in London were happy with an influx of cheaper nannies, gardeners and labour.

Former Conservative prime minister Sir John Major has, meanwhile, said the Leave campaign's "splendid isolation" approach would leave the UK weaker.

He told Leave campaigners to "go to North Korea" if they want "undiluted sovereignty".