Abigail Saxon, 34, who works on Radio 4's Sunday Programme, is said to have streaked twice around Manchester's Barca restaurant during an office Christmas lunch, allegedly for a £100 bet.

She is then reported to have completed a third tour, shouting: "This one is for free."

Diners in the packed restaurant - which is part-owned by Simply Red singer Mick Hucknall - whistled and cheered.

The BBC has now launched an investigation into the conduct of staff from the religious programmes department, which is based in Manchester.

The office Christmas lunch took place in a crowded restaurant

A claim that Ms Saxon was "egged on" by a senior executive, David Coombes, is also being examined.

Both members of staff will learn the result of any disciplinary hearing in the New Year. Both were at work on Tuesday, following the incident last Thursday.

Ms Saxon, who lives in the Rusholme area of the city, is said to have stunned her colleagues when she accepted the challenge.

She is reported to have gone to the lavatory, removed her clothes apart from her socks, and pointed one leg out of the door, shouting: "Here I come."

A BBC spokeswoman said that the lunch had been a team event and not a departmental affair. It had been paid for by the staff themselves, she said.

A statement from the corporation said: "A Christmas celebration got seriously out of hand.

"The BBC would not under any circumstances condone such behaviour.

"Officials are investigating the matter and will take the appropriate disciplinary action."