The architects behind a proposed 1,000ft bud-shaped skyscraper in the City have started an appeal against Mayor Sadiq Khan’s decision to block it.

The Tulip, designed by Foster + Partners and backed by developer Jacob J Safra, will now go to a planning inquiry later this year.

Tower Hamlets formally objected to the Tulip, arguing it would "seriously harm" the view from the Tower of London.

Council officers said the skyscraper would have a "significant" adverse effect on the setting of the Grade I-listed 11th century fortress, which is just 600m from the proposed development site next to the Gerkin.

The building would also complicate transport infrastructure and add to pollution levels in the borough, according to a Tower Hamlets report.

Plans for the 300-metre-high viewing platform and "classroom in the sky" were originally approved by the City of London Corporation in April last year. But the decision was overturned by City Hall in July. A final decision will now be made by central government.

Mr Safra said: "We are confident in London's role as a global city and in the expertise and dynamism of the people of the UK, and are delighted to offer schoolchildren state-of-the-art classrooms in the sky to appreciate London's history and career opportunities. Our investment in The Tulip offers significant public benefits to residents, workers and visitors, and will generate considerable economic benefits for the country."