Its forward order book has dropped by almost £500m, it said today.

Forward orders currently stand at about £1.56bn against £2.1bn a year ago.

Completions are down 5.5% since the start of the year, while net private reservations are 33.6% lower than the year before.

Barratt noted a significant drop in net private reservations per week since the end of March, with an average of 206 over the last six weeks.

The deterioration in market conditions since the end of March has forced the business to be selective about which sites is starts, so the number of sites is expected to decline in the next financial year.

"Despite the deterioration in current trading conditions, we expect to deliver a satisfactory outcome for the current financial year," said chief executive Mark Clare.