A magnificent mansion, described as having 'ambassadorial proportions', is for sale for an equally magnificent £15m.

Estate agents, Knight Frank, describe the six bedroom property as 'an incredible period home that has been transformed by the current owners to offer ambassadorial proportions'.

It sits at the entrance to the St Margarets Trust Grounds, close to the banks of the River Thames.

The agents add: "The inspiring spaces have been carefully constructed to allow exceptional light and volume to flow through the house, creating an elegant and sophisticated environment to live in.

"The property is arranged over four principal floors and provides expansive reception space, luxurious bedroom suites and outstanding leisure facilities."

There is a stunning cantilevered marble staircase which is an incredible feature and provides the centrepiece to the raised ground floor.

"A magnificent reception room with high ceilings, feature fireplace and solid oak parquet floor is positioned to the rear as is the dining area, with access out to the delightful terrace that runs the full width of the property and overlooks the garden, the Trust Ground and the River Thames."

The lower ground floor offers wow factor leisure facilities including a beautiful indoor/outdoor pool, fully equipped gym, sauna, bar and cinema room.

Knight Frank said: "The clever design of the pool allows you to swim from inside to outside by glass arches rising up."

They added: "Moving to the first floor there is a sumptuous principal bedroom suite with en suite bathroom and bespoke marble finish. There are wonderful 'green' views towards the River Thames and Old Deer Park in the distance. Two elegant dressing rooms follow and an additional bathroom.

"The accommodation is complete with three further spacious bedrooms, all of which have an en suite. This floor provides an excellent area to accommodate visiting guests or children's room.

"There is a fine roof terrace on this floor which has great views of the area and two further balconies off the front bedrooms."

CCTV systems provide guaranteed high levels of security, while there is a lift to all three floors.

The mansion is set on St Peters Road and falls within the exclusive Pleasure Gardens which are made up of three trust grounds (The River Grounds, The Lake Grounds and the Avenue Grounds) that total around 12 acres, and are for the exclusive use of its residents.