NB Real Estate has said that the percentage of empty office space in the City of London had risen by more a tenth in the last quarter to 11.9%.

More than 10m sq ft of office space now lies empty in London’s financial district as the recession tightens its grip and increasing numbers of businesses collapse or downsize.

Approximately 11.9% of City offices are vacant – equivalent to 10 large city towers – up by a 10th already in 2009, and more than double the figure of 5.2% from before the onset of the credit crisis in 2007, .

It is first time since 2004 that empty office space has breached the 10m sq ft mark.

The slump is placing immense pressure on rents, which have now fallen 27% in the past year from an average of £65 per sq ft to £47.50. Increasing supply through the completion of new developments is hastening the fall in rents, although the situation is even more dire in the West End.

The Times, Daily Telegraph