POLICE negotiators, supported by armed marksmen, were last night playing a waiting game in their efforts to bring an end to a siege at one of Scotland's most unusual tourist attractions.

The stand-off is taking place at Scotland's Secret Bunker, a maze of tunnels and rooms 100ft under the Fife countryside once earmarked as the seat of the Scottish government in the event of a nuclear attack.

Officers were watching the man's increasingly bizarre behaviour on closed circuit television cameras.

Jim Braid, the general manager at the bunker said it appeared the man was ''enjoying playing at soldiers''.

The incident involving what is now a museum in Troywood, near Anstruther, began around 1.30am yesterday when the man, with the help of a JCB digger, broke into the building.

Police, who were making no effort last night to flush him out, said that it hoped that the incident would be resolved ''as soon as possible'' and without any injuries.

However officers and the museum authorities have accepted that the intruder, who is believed to be from Cupar, had enough food and drink to stay holed up in the bunker for days.

Firearms officers were called in because the attraction houses knives and firearms which they feared could be used as weapons.

The police said it was not yet known what the unnamed man's intentions were, or whether he was armed when he entered the premises using the JCB to knock down a perimeter fence topped with razor wire.

Once inside, he activated hermetically-sealed three-tonne blastproof doors.

Alan Maich, a chief superintendent, said: ''Due to the complex layout of the structure and the fact that he will have access to replica firearms and weapons, caution is being executed.

''There is a CCTV system that has been of limited value. The bunker is two floors below ground level and there is no natural light and there are lots of different compartments.''

Earlier, as police marksmen and trained negotiators gathered on the outside, the man appeared to engage in a bizarre game of soldiers on the inside.

Caught on CCTV, the intruder spent hours roaming the facility, at times removing food and drink from its bar and restaurant.

At one point he fell asleep in a suite of rooms once reserved for a secretary of state for Scotland in case of attack and alarms were activated by the police to wake the intruder up.

Cameras caught shots of him stripping army uniforms from mannequins in the museum's displays before dressing himself as a soldier.

He was spotted exploring the once secret nuclear hideaway with what was believed to be one of the decommissioned guns.

He was also seen to place barricade-style booby traps at strategic points throughout the bunker.

Last night, Mr Braid said that he was in no doubt that the man was ''enjoying playing soldiers''.

He said: ''There is a range of weapons but they are all deactivated. He also laid wires at various places as if he was making booby traps. We don't think these are connected to explosives, although we obviously can't be sure of this''.

Mr Braid added: ''He could stay there for a long time with the food and drink from the canteen.

''He is probably having a slap-up meal as we speak.''

The museum manager voiced concerns about what effect the break-in could have for the attraction as many of the exhibits the man had been playing with were irreplaceable.

''The longer the man is in the bunker the more risk there is of him doing damage. We have very important things down there donated from bunkers and RAF bases around the country and from as far away as China and Singapore. There are things in there that could never be replaced.''

Earlier this year, Tom Hanks, the actor, visited the attraction with his daughter, a student at St Andrews University.