The firm posted losses of £572m for the first quarter compared with profits of £266m in the same period a year ago.

Underlying profits, which strip out the fall in property values, dipped from £76m to £74m while asset value fell 9.8% in the quarter, less than estimated by analysts.

The company has said its 'Cheesegrater' development in the City of London is likely to be delayed until at least 2012.
 
The development at 122 Leadenhall will not meet its initial 2011 completion date, as the company undertakes a cost review of the project.

It said it continued to press ahead with the rest of its development portfolio, which includes the completion of 201 Bishopsgate in the City of London, and additions to the Sheffield retail centre Meadowhall.

Shares in the company rose slightly to 724.50p early this morning.