A man impersonating the Kentucky Fried Chicken founder Colonel Sanders managed to dupe his way into the UN headquarters in New York and shake hands with a senior official.

Dressed in the fast food icon's familiar white suit and black bow tie, the actor evaded tight security to gain access to the restricted areas of the complex.

He even posed for a photograph with Ali Treki, former Libyan foreign minister and new president of the UN General Assembly, before the alarm was raised and he was ejected.

A spokeswoman for Ban Ki-moon, the UN secretary-general, yesterday said that an investigation had been launched into the security breach, which was dreamed up by KFC as a promotional stunt.

"It should not have happened – that I will stress, and very strongly," Michele Montas told Canwest News Service, the Canadian news agency.

"There was some lapse in security and the individual in question was, on the initiative of one security guard, taken into the UN."

As part of its campaign to promote a new menu range, KFC is "lobbying" the UN for the fictional Grilled Nation to be accepted as a member state.