Work will begin on the UK’s tallest residential tower, South Quay Plaza in Canary Wharf, after Mayor Boris Johnson gave it the stamp of approval. The 220m-tall structure designed by architects Foster and Partners will provide 888 homes, of which 188 will be affordable.

One part of the proposed double-tiered structure will rise to 220m and 68 storeys while the other spreads across 56 floors, topped by a roof garden.

The plans, submitted by developer Berkeley Homes, gained permission from Tower Hamlets council last year. But the scale of the scheme and its effect on London’s skyline required further approval from the Mayor.

Construction will begin in July 2016 following demolition of a 1980s office block on the current site. The tower is scheduled for completion in 2021 when it will become the UK’s tallest residential tower. It could quickly be eclipsed by City Pride, a 239m tower by Squire and Partners, which has already been recommended for approval by Tower Hamlets council despite complaints that it will block light to neighbouring properties.

South Quay Plaza is just one of 263 proposed towers (buildings of more than 20 storeys) in London, according to figures from New London Architecture (NLA) and GL Hearn. Tower Hamlets has seen the most activity, with 18 buildings under construction and a further 27 with planning permission.