One of the most prominent Tories in City Hall has pledged to lobby the Mayor of London to reject controversial plans for a 24-storey tower block in Swiss Cottage.

Andrew Boff, leader of the London Assembly Conservative Group, has promised he will do his best to convince Boris Johnson to reject plans for the building at 100 Avenue Road.

Under planning laws, any application to develop a building more than 30 metres high outside the City of London must have the approval of the mayor to go ahead.

Mr Boff discussed his opposition to tower blocks at the launch of Camden Conservatives’ local election manifesto at Old Hampstead Town Hall, in Haverstock Hill, Belsize Park, last week.

He said: “We have a slightly different view than Boris about tall buildings: 230 planning applications have been granted in London for skyscrapers and tall buildings.

“His view is that it is a symbol of the vibrancy of the economy in London and our view is that it is also becoming just the same as everywhere else.

“No family should be placed above the third floor of any property and for as long as we keep building tower blocks, people are going to be tempted to put families in them and that is not the kind of place where families should be brought up.”

In February, developer Essential Living submitted an application to Camden Council to demolish the building – which houses the Ham&High and other offices – and replace it with a tower block containing 184 flats.

If the council decides to reject the planning application, the mayor has the power to “act as the local planning authority” and overrule the council’s decision.

Last month, City Hall officials wrote to Camden Council informing officers that Mr Johnson supported the “principle of the development” but that the application did not fully comply with the London Plan.

Camden Conservative leader Claire-Louise Leyland told the Ham&High she had discussed residents’ concerns about the development, including 500 official objections to the application, with Mr Boff and that he had agreed to raise the concerns with Mr Johnson.