A proposed challenging behaviour unit in the grounds of the old Half Tree Hollow School has been recommended for approval.

Plans include nine bedrooms, a sensory room, a “time out” space and a seclusion room, laid out in two blocks linked by a covered walkway, with a courtyard in one of them. Facilities to care for people with physical disabilities are also included.

St Helena’s health service currently looks after people with severe behaviour disorders at nearby Sundale House, but the building is needed for other purposes – including a new prison.

The building will be 28 metres long and just under six metres high, except for an upstairs area for staff over the main lounge and lobby.

It will be built of stone masonry and concrete blockwork, with a metal sheet roof.

A report says neighbouring properties will not be affected.

The planning board has been advised to approve the scheme, but with various conditions to protect the environment.

They include collecting rain water for re-use, using solar panels for all water heating, with concealed tanks, and relying on natural ventilation, rather than air conditioning.

They also say a landscaping scheme must preserve the rural character of the area, and there must be no light pollution.