Graham Wildin’s extension has a two-lane bowling alley, 16-seat cinema, squash courts, a private casino and a bar.

The complex also boasts a soft play area, indoor tennis and badminton courts and a 25ft-tall three-storey doll’s house.

Mr Wildin believed he did not need permission when he started construction last year - but council officials say the building breaches planning laws and have ordered him to return the land to its original state.

The grandfather said he built the facility 18ft-deep - removing 9,000 tonnes of soil - to ensure it would not block his neighbours’ views.

He said: “This is my family home, all my children and my grandchildren come to visit, it’s the place they all go.

“Nobody really knows it’s there, if all this fuss hadn’t been kicked up nobody would know it was there.”

Mr Wildin has not revealed the cost of building in the back garden of his six-bedroom home in Cinderford, Gloucestershire.

He said: “If you look at the building from the street you can’t see it at all, you can maybe just see a fence. You’d have to be in a helicopter to see it.

“I looked at the rules permitting development before I started, they are very generous rules.

“As far as I am concerned I have permitted development rights, there are five steps that must be adhered to, and this qualified in all of those.

Mr Wildin’s neighbour, Andy Buckmaster, whose property backs onto the complex, is the only neighbour to object to the building.

He said: “As far as I know, you’re allowed to build a ‘shed’ in your garden that should not exceed 50 per cent of your garden.

“At night, it is extremely quiet and one of the quietest places you could live.

“But the other night he had a practice with his skittle alley and it sounded like it was in my house - it was unbelievable.”

Forest of Dean District Council said it does not believe planning permission should be given and has told Mr Wildin to remove the building and reinstate the land to its original level.

The enforcement notice for breach of planning control stated: “The construction of walls and the erection of a building on the area of land which has been excavated is harmful to the residential amenity of the surrounding land in terms of the overbearing impact of a physical structure and the level of impact from the uncontrolled use of the building.”

Mr Wildin is appealing the decision, while the council has said it is “looking for a workable solution”.