Boris Johnson has committed to taking part in a Conservative Party leadership debate with other candidates on the BBC next Tuesday.

But the frontrunner in the contest has not yet agreed to appear in the earlier Channel 4 debate on Sunday evening.

In an interview with BBC Radio 4′s World at One programme, Johnson said he was “more than happy” to take part in the corporation’s debate.

But he added while he was “very keen” on debates but did not want too much “blue-on-blue action”.

The BBC’s debate will take place in the evening after the second round of voting in the contest when the number of candidates will have been reduced to five or fewer.

Channel 4 has threatened to represent Johnson with an empty chair if he fails to turn up to their debate at the weekend.

All the other candidates have agreed to take part, with Dominic Raab, Jeremy Hunt, Michael Gove and Sajid Javid all signing a pledge.

Johnson said today: “I think it is important that we have a sensible grown-up debate.

“My own observation is that in the past when you’ve had loads of candidates, it can be slightly cacophonous and I think the public have had quite a lot of blue on blue action frankly over the last three years.

“We don’t necessarily need a lot more of that and so what I think the best solution would be would be to have a debate on what we all have to offer the country and the best time to do that I think would be after the second ballot on Tuesday and the best forum is the proposed BBC debate. I think that’s a good idea.”

Hunt this morning ramped up the pressure on Johnson with a warning Winston Churchill would not approve of him “hiding” from media scrutiny.

It comes after Matt Hancock, the health secretary, dropped out of the race today.