ITV's former South Bank studios are set to be flattened for offices after Sadiq Khan refused to block the plans.

Residents had hoped the mayor of London would pull the plug on developers' proposals to build a 25-storey tower on the site.

But Labour's Mr Khan has refused to halt the project. The future of the ex-studios now lies in the hands of Lambeth Council, which already approved the plans in March. 

The decision is a blow to campaigners who have argued the tower will blight the London skyline for generations. More than 4,000 people have signed a petition calling for Lambeth Council to throw out the plans and Labour MP for Vauxhall Florence Eshalomi has criticised the absence of housing and affordable workspace in the scheme. 

But a City Hall report said the harm to the skyline was outweighed by the benefits of the project. The report dated August 22 reads: "It was concluded that the height and mass of the proposed building would result in some harm to nearby heritage assets, namely the character and setting of the South Bank Conservation Area and the Grade II IBM Building. 

View of the planned development from Waterloo Bridge CREDIT: Make Architects

"Officers have reached the conclusion that whilst less than substantial harm would be caused to these heritage assets, this would be outweighed by the public benefits of the scheme." 

The offices will create up to 4,500 jobs in the borough once finished, according to council planning officers. Businesses will be able to rent affordable workspace for 15 years at the offices, with prices starting at £10 per sq metre.

Campaigners blasted Mr Khan's refusal to intervene a 'mistake' and called for a public enquiry. Local resident and SOS Save Our South Back Action Group chair, Jenny O'Neil said: "The mayor's mistakes only illustrate further the need for a public inquiry. This is a very prominent strategic site, and this scheme will blight the South Bank, with social housing residents enduring health issues with the huge daylight losses. Sadiq has failed to act strategically or protect the rights of residents".

Developers, Mitsubishi Estate and CO-RE, who are working on the project alongside Make Architects, say once finished the site will include rehearsal space, a gallery and riverside cafes and restaurants. They said: "Our proposals to transform a dormant, closed-off central London site into a new mixed-use development that prioritises high-quality workspace and the provision of new arts and cultural space will be a great addition to the South Bank."