The Mayor of London says “this is not a time to be lowering our ambitions”, calling on the government to continue investment in the arts.

Johnson warned that private sponsorship could not be relied upon in the face of public spending cuts. He says he understood why there are real concerns about 30 per cent cuts to the Arts Council.

“London’s arts and cultural organisations already do a great job at fundraising, but they can’t be expected to defy the laws of economic gravity in a prolonged downturn and in the face of necessary austerity measures,” he said.

I am advocating through my Cultural Strategy that continued support and investment in the creative economy is crucial

Johnson was speaking out at the launch of Cultural Metropolis, his arts strategy for London, which sets out to create opportunities in the arts and enhancing London’s appearance. It also looks at how the 2012 London Olympics can be used to further the Capital’s prospects.

He added: “Creative thinking and innovation is vitally important to the health and wealth of this great city and that is exactly why I am advocating through my Cultural Strategy that continued support and investment in the creative economy is crucial to sustaining the wellbeing of London and the nation.”

The Capital receives 69 per cent of all private arts funding in the UK. Johnson confirmed that the economic slump has seen a plunge in private sponsorship and donations.