However, the Federation insists that there is no evidence at the moment to suggest anything other than merchants responding to market fluctuations.

BPIF head of corporate and external affairs Cicely Brown said: "There is no evidence of an official cartel or smoke-filled rooms. But we are keeping a constant eye on paper and pulp rises."

The BPIF forged closer links with the OFT following a letter from David Bland, operations director of member company Alderson Brothers (PrintWeek, 15 March), and will share any information provided by members.

Blands letter was prompted after several merchants including Robert Horne, Howard Smith Paper, Bunzl Fine Paper, Premier Paper, Papyrus and Antalis announced price rises within a week of each other.

Brown said that the next issue of the BPIFs members magazine, Action, would call for any evidence of unfair practices.

The OFT revealed that the UK and European paper industry had been informally investigated on multiple occasions in recent years, but said it had not uncovered concrete evidence, unlike that found in the recent carbonless cartel (PrintWeek, 4 January).

At the start of the year Arjo Wiggins Appleton was fined 115.1m by the European Commission for its part in a carbonless cartel between 1992 and 1995. The Commission also punished Carrs Paper, Mitsubishi HiTec Paper Bielefeld and Zanders Feinpapiere.

Story by John Davies