The firm, which was probed along with other companies by the OFT for the potential price fixing and market share violations, said it had "voluntarily ended the questionable arrangements".

However, the OFT found that two businesses "colluded to fix the prices of and the market share for stock-check pads", used by restaurants and other firms to note orders.

Bemrose Group, and subsidiary BemroseBooth, was initially faced with a penalty of nearly 1.9m, which was reduced to zero for providing information that "uncovered the cartel and led to a successful finding of infringement".

Achilles Paper Group had its penalty of more than 255,000 halved for giving the OFT evidence of the cartel. 4imprint Group, which previously owned Bemrose's check pad business, was fined more than 40,000.

BemroseBooth chief executive officer Graham Bennington said: "This matter was limited to a very specific part of our business and a few individuals.

"Since 2003 we have implemented a robust education programme and are confident we are in full legal compliance."

OFT director of competition enforcement Vincent Smith said he was determined to detect and punish those involved in "anti-competitive agreements".