Boris Johnson has said it is “not true” he was kept in the dark over some sensitive secret intelligence by Downing Street when he became foreign secretary.

The BBC and The Sun newspaper, citing sources, claim the Tory leadership front-runner was not shown a category of information when he entered office in 2016.

Speaking at a leadership hustings on Friday morning, Johnson denied he “couldn’t be trusted” by Theresa May with intelligence information.

“It’s not true. But, I obviously can’t comment any further on intelligence matters,” he said.

“I am sure that the prime minister would not comment on intelligence matters either so I am extremely dubious about the provenance of this story. It’s not true and I don’t comment on intelligence matters.”

A Downing Street spokesman said: “We do not comment on intelligence matters.”

The BBC, citing “multiple sources with direct knowledge of events” who are not involved in the leadership campaign or politics, reported Number 10 did not want Johnson to be shown a category of sensitive secret intelligence.

The Sun claimed nerves were sparked when Johnson was accused of revealing classified information by mistake.

A source told the paper: “The PM didn’t think Boris could be trusted because he had a loose tongue. He made the agencies anxious. He wasn’t told everything because of that.

“Pre-meetings would be arranged without his knowledge before he’d come over to No. 10.

“They probably both share the blame for the situation, and it was a clash of their worst traits – Boris is a big mouth and Theresa can be a paranoid control freak.”