The work, which is expected to be worth around £1.7m each year, covers between 30 and 40 mailings each year of up to 290,000 copies as well as other work such as direct response card inserts.

RSPB's magazines however, such as its flagship Birds title, will be kept in house. Tim Norman, head of logistics at RSPB said that it had longstanding relationships with printers to produce the magazines and members have high expectations.

"There's no publication date on Birds, but even if it arrives two or three days late, we hear about it," he said.

Charterhouse won the work through a competitive tender. The incumbent was Dialogue Solutions and prior to that the RSPB handled its DM work in house.

Norman described the company as having an "innovative approach to communications". He said Charterhouse was rolling out numerous projects such as a course for RSPB staff to guide them through print terminology.