Chris Evans has hit a major road block in his new role hosting Top Gear after realising he finds it nearly impossible to speak while he is driving.

The motormouth presenter can hardly breathe for chatting on his Radio 2 breakfast show.

But when it comes to talking from behind the wheel, he is said to freeze like a cat caught in the headlights and struggles to blurt out any of his lines.

It is the latest in a line of setbacks to hit the relaunch of the BBC flagship show, including allegations of 'meddling' by Corporation bosses and high-profile resignations.

The show's new production team are also said to have limited knowledge of cars and there are suggestions that production on the new series is behind schedule.

Chris Evans has hit a major road block in his new role hosting Top Gear after realising he finds it nearly impossible to speak while he is driving

Jeremy Clarkson, Richard Hammond and James May were all masters of the art of speaking to camera while zooming around in the latest top-of-the-range sports car.

The former Top Gear trio managed to complete most of their on-road segments in a single take.

But for Chris, it can take up to ten attempts before he finally gets it right - much to the annoyance of the programme's hard-pressed crew.

A source told The Sun: 'Chris is really struggling to master the art of driving and talking to camera, which is crucial.

'He is in a massive sweat about it because he often ends up fluffing his lines.

'The professional drivers are doing a lot more to cover for him and the camera crew are getting frustrated.'

The issue is the latest in a long line of setbacks to hit the new-look show, set to first air on May 8

Staff are reported to have accused BBC2 controller Kim Shillinglaw (left) of 'meddling' in the programme's development - something said to have been a factor in the departure of key backroom staff, including executive producer Lisa Clark and script editor Tom Ford.

A BBC spokesman said: 'This 'story' is complete nonsense and the truth is that Top Gear producers have been blown away by how quickly Chris has taken to talking to camera whilst driving at speed, a skill which has taken some presenters a long time to master.'

The issue is the latest in a long line of setbacks to hit the new-look show, set to first air on May 8.

Staff are reported to have accused BBC2 controller Kim Shillinglaw of 'meddling' in the programme's development - something said to have been a factor in the departure of key backroom staff.

Executive producer Lisa Clark, who Evans personally brought in to lead its revamp, announced in December she was quitting the show after just five months.

She was hired following the departure of Andy Wilman, who left the BBC following close friend Clarkson's departure and will join the old Top Gear line-up on their new Amazon motoring show.

Corporation bosses had their reservations about Evans taking over from the outset, and BBC2 controller Kim Shillinglaw said she was 'terrified' at the thought of the presenter taking the lead.

Jeremy Clarkson, Richard Hammond and James May were all masters of the art of speaking to camera while zooming around in the latest top-of-the-range sports car. But for Chris, it can take up to ten attempts before he finally gets it right - much to the annoyance of the programme's hard-pressed crew

The BBC chief, who is known for her direct approach, said she was 'so excited about the new series' but admitted 'you don't quite know what is going to happen next'.

Evans will be joined by former F1 driver David Coulthard, German racing driver Sabine Schmitz and motoring journalist Chris Harris when the programme launches next May.

But questions have been raised over whether Schmitz and Harris are well-enough known to add to the show's appeal.