The BBC was engulfed in another decency row today after one of its highest-profile stars exposed himself live on air.

The corporation was forced into another embarrassing and potentially damaging apology after Doctor Who actor John Barrowman revealed himself last night, in a pre-watershed Radio 1 show which was also broadcast online via a webcam.

Indecent exposure: Barrowman got his 'fruit and nuts' out live on air

In an interview on The Switch at 8.15pm, Barrowman, 41, performed the act after being prompted by presenters Annie Mac and Nick Grimshaw.

The Scottish-American actor, best known for his role as Captain Jack Harkness in Doctor Who and its spin-off series Torchwood, made the studio erupt in screams and wild laughter, while a producer hastily covered the webcam.

The incident occurred despite BBC directorgeneral Mark Thompson's promise of greater controls following the outcry over the Russell Brand and Jonathan Ross obscene cal l scandal.

Producers have been warned that swearing and potentially offensive output must be approved by the controller of each station or channel.

Barrowman, who appeared on the show to promote his new single What About Us, exposed himself after presenters asked about his penchant for removing his pants.

Grimshaw said: "You're famous, we're told, for getting your willy out in interviews. Is this going to happen today? Should Annie be careful?"

Barrowman asked: "Is the webcam on?", and when told it was, responded: "All right. I'll get it out for you then, no problem."

Annie Mac was then heard screaming and shouting: "Oh my God!" as Grimshaw and Barrowman laughed. Seconds later Barrowman said: "I didn't take the whole thing out, but I got my fruit and nuts out." The show then continued, with both presenters laughing and expressing their surprise, but neither condemning or apologising for their guest's actions. Even Bar rowman seemed surprised, exclaiming: "I can't believe I've just done that."

Screamed: Radio 1's Annie Mac

The openly gay actor has appeared as a judge on the prime-time BBC talent show Any Dream Will Do, as well as in major West End musicals. The BBC confirmed Barrowman had exposed himself on the programme, but said it was not visible to online viewers. A BBC spokesman acknowledged the programme had "overstepped the mark" but said Mac had apologised at the end of the broadcast and no complaints had been received last night.