Boris Johnson has launched a fresh attack on David Cameron for "shamefully" spending £9.3 million of taxpayers' cash on a pro-EU leaflet.

London's mayor rounded on the "scare" tactics of the remain campaign as he continued his northern "Brexit blitz" tour.

But the start of his speech was interrupted by hecklers shouting "no Tories in Newcastle" and a group of women with at least one small child with them were escorted out.

Mr Johnson joked that when he cycles around London people know who he is and shout out things at him "like those kindly people" who disrupted the event.

The Herald: Boris attacks PM over spending on EU 'remain' leaflet.Boris attacks PM over spending on EU 'remain' leaflet.

He told the crowd that, unlike anonymous politicians and bureaucrats in Brussels, voters can hold him accountable.

"They know who I am, they know what I do. Who knows what's going on in Brussels?"

In a swipe at the Prime Minister, Mr Johnson said the remain supporters were "shamefully spending £9.3m of taxpayers' money on a leaflet trying to scare everybody into remaining in the EU".

"In the scare tactics of project fear they are woefully underestimating this country and its people and what we can do."