The existing listed Grade II* building at 10 Trinity Square is the former Port of London Authority (PLA) building by Sir Edwin Cooper, which was built in the Beaux-Arts style with a central courtyard, and faced with Portland stone. The building is perfectly square in plan apart from the three-storey entrance, a grand Corinthian portico with columns surmounted by a flat-topped masonry tower containing a series of sculptures. The courtyard originally contained a single storey central rotunda, which was destroyed by enemy action during World War II. In 1973, an eight storey office block replaced the destroyed rotunda and a single storey roof extension was added on the main building.

The former PLA building will now be converted to a high quality hotel with 121 bedrooms and 30 private residential apartments, as well as a public restaurant, conference facilities, meeting rooms and a gymnasium/spa. The basement would house a circular ballroom. The plan is to demolish the 1973 central courtyard building and rooftop structures, and a new structure incorporating a glazed central rotunda would rise within the courtyard to roof level where it would radiate outwards to form the sloping roof of a two storey extension. The new structure supporting the glazed skin will have a cross-section like an ‘hourglass’, rising from 12 inwardly inclined columns in the circular ballroom at basement level, through the rotunda to define the perimeter of the dome, and then stretching outwards and upwards in the form of a cone to the new roof. The domed roof and the floor of the rotunda will be glazed, allowing natural light to penetrate to the basement ballroom and providing views upward towards the masonry tower over the main entrance.

Extensive works are also proposed at Seething Lane Gardens, which regrettably will be removed but replaced with a new larger landscaped garden that will provide more open, accessible space located where the service road currently lies. Improvements will also be made to two nearby open spaces, Trinity Square Gardens and St Olave's Churchyard, to mitigate the loss of Seething Lane Garden during its closure. Access from the street to the basement areas will be via two new pavilions at the north and south of the garden.

The Committee praised the innovative design of the new courtyard building and roof structure, which will contribute to the richness of architecture in the City and to the character of the building, the conservation area and the surrounding area in general. Planning permission and listed building consent were granted subject to the Mayor of London (in accordance with legislation) being given the 14 days to decide whether to allow the Corporation to grant planning permission and to conditions, planning obligations and other agreements.

Contact Tia Cox, 7332 3865