The Leeds-based company said that, while it wanted to strengthen its green credentials for genuine environmental reasons, it found that an increasing number of clients were specifying certified products.

Managing director Malcolm Carter said: "We were not awarded these particular contracts because we achieved certification, but there is no doubt they have a definite bearing on the ability to win business from existing and new clients."

All of the company's waste, including cardboard, paper, polythene, plates and chemicals, is segregated and collected by relevant recycling companies.

Carter said: "The majority of the large envelope users, such as banks and insurance companies, are very keen on minimising the cost of printed material to the environment and wish to be seen to be doing so."

According to Carter, FSC and PEFC is increasingly becoming a prerequisite throughout the industry, however, he said that FSC accreditation carried "a substantial cost to a business of our size".

"From a business angle, the cost has to be justified. We believe that it is due to the fact that we are now not excluded from quoting on certain campaigns, which had definitely occurred in pre-accreditation days."

First Class Post has 30 staff and is a trade supplier with a customer base of 500, including mailing houses, printers, agencies and print management companies.

The £3m-turnover company operates a mix of nine envelope overprinting machines that enables it to print up to four colours across a range of envelope sizes and finishes.