Unstable ground, £1.9 billion rate bombshell set to knock London businesses off their feet.

It emerged today that London firms are to be hit with a huge business rate tax increase over the next five years.

Following the sharp rise in property prices in the run up to the recession companies in the capital could face rises of thousands of pounds, something which politicians have urged the government to address as many firms are already struggling to tread water and stay affloat.

Shadow London Minister Justine Greening has said: "London businesses will face significant business rate tax rises at the very time they can least afford it. The Government should be helping firms not kicking them while they are down and struggling to get back on their feet."

The proposed £1.9billion increase will see Westminster fair the worst, with its average rateable value up £47,000 last year compared with five years earlier. The second highest was Camden at £24,000, followed by Kensington & Chelsea at £22,000 and the City at £18,000.

The tax is based on property valuations as at 1 April last year, since when commercial rents in London have fallen by up to 40 per cent.