Thousands of bids for construction contracts worth £500m have been rigged, the Office of Fair Trading has revealed (OFT).
The government watchdog said the evidence it has uncovered is just the tip of the iceberg. In the east Midlands alone, it claimed, 1,000 contracts have been won by firms involved in unfair cartels.
Most of the information the OFT received was as a result of its amnesty on whistleblowers volunteering information about anti-competitive tactics. The organisation's 'Come Clean on Cartels' month came to an end this week.
Philip Collins, OFT chairman, told the Guardian: "Based on this modest sample, you can get an impression of the possible national scale of the bid-rigging problem."
Collins, who was recently appointed as the OFT's chief, said his organisation plans to increase the pressure on companies to cooperate with investigations by prosecuting firms which fail to hand over requested documents.
He added that the OFT would also change its practice of relying on complaints from consumers and businesses before launching an inquiry.
"You can expect to see a change in the balance of the cases we take forward," Collins said.
"Some will continue to be complaint-led. However, we expect a proportion…to be intelligence-led, that is own-initiative cases."
