Plans to build a three-storey modern house with basement swimming pool and gym on the site of a historic Hampstead parish jail have been lodged with Camden Council.

The grade-II listed lock-up, in Cannon Lane, dates back to 1730 and was where prisoners were kept after appearing at the local magistrates court in neighbouring 18th century mansion Cannon Hall, which later became the home of novelist Daphne DuMaurier.

The proposed new six-bedroom “low energy” house will replace an existing low-profile modern one-storey home built in the 1980s.

The existing house, which incorporates the lock-up as its entrance, is hidden from the street behind a high listed wall, which is mentioned in the Hampstead Conservation Area statement.

Although a modern house already exists on the plot, the new application is still expected to attract the attention of local conservationists due to the site’s historic significance.

The application was submitted by Greenway Architects at the end of January. It proposes six bedrooms over three floors, comprising basement, lower ground, upper ground and first floor levels.

The basement will house a pool, gym, wine cellar and utility space. Staff quarters will also be built above the old lock-up.

The application states: “The intention is to create a high-quality, sustainable, low-energy house” that will enhance the area’s character.

The HCAAC has been consulted for its views, as have the owners of neighbouring Cannon Hall, which is currently on the market for £28million.