Unimer plc, the invoice clearing house for the building products industry, processed transactions worth £739m for the 12 months ended April 2009 – a 13.6% decrease on a year ago.

Howard Grant, Unimer’s managing director, said the construction sector’s unprecedented downturn had led to Unimer facing its most “challenging trading period in living memory”.

The organisation also said last year was the worst ever in terms of business failures among its membership

Unimer has reduced staff numbers by 20%, due to less volumes but also reflecting a significant growth in electronic transactions and uptake of the Unimer online system.