Nigel Farage has blamed immigration for failing to turn up at a UKIP event in Wales at which 100 people had paid £25 each to meet him.

The UKIP leader said that population growth had resulted in a snarled-up M4 motorway that made the journey take far longer than expected.

He has been accused of a lack of professionalism after failing to attend the “Meet Nigel Farage” evening in Port Talbot.

“It took me six hours and 15 minutes to get here – it should have taken three-and-a-half to four,” he told BBC’s Sunday Politics Wales.

“That has nothing to do with professionalism, what it does have to do with is a country in which the population is going through the roof chiefly because of open-door immigration and the fact that the M4 is not as navigable as it used to be.”

The comment was immediately attacked by Labour with the shadow Welsh secretary, Owen Smith, tweeting: “Thought I’d heard it all but @Nigel_Farage has just blamed immigration for clogging the M4 and making him late for his keynote speech.”

He added that the remarks made Mr Farage “dangerous” – and said he was using “dog-whistle politics”.

But Mr Farage was not backing down, hitting out at other “vanilla” politicians who failed to speak their minds.

He then took to Twitter about his view, writing: “Can’t make it up: Tory minister says immigration strains roads and no one bats an eyelid. I say it and Mail & Telegraph fake outrage.”

It came after he announced that UKIP had appointed Paul Lambert – a former BBC producer known as “Gobby” for his famous shouts at the Prime Minister and others – as director of communications. Mr Farage described him as “one of the best in town”.

And another senior UKIP politician – MEP Patrick O’Flynn – admitted that Mr Farage was a domineering figure in the party, saying: “It’s not just Nigel Farage but clearly we have a party leader who leads, which is a bit of an innovation in contemporary politics.”

The former journalist added: “I remember Tony Blair in my days as a journalist saying to me ‘you are either a control freak or you have lost control’.

“And if you have to decide which side of that fence to go on, then having control is probably the right option.”