The Office of Fair Trading (OFT) will maintain a vow of silence over its bid-rigging investigation until it makes an announcement next year on the level of fines companies will receive.
The 112 accused contractors are currently making submissions to the OFT following the release of its Statement of Objections last month.
But the authorities will not reveal which firms are fighting the charges, or the names of contractors facing the most serious allegations of receiving compensation payments.
Contractors will be left hanging for months while the OFT decides their fate. Innocent firms also face losing work as everyone is tarred with the same brush due to the OFT's stance.
A spokeswoman for the OFT said: "We won't say anything until we are in a position to find out whether people are guilty. And I am sure we won't see any fines until next year."
A Construction Confederation spokesman warned that the OFT's silence would create a bottleneck on public sector work.
He said: "Some public sector clients are delaying work on contracts until there's an outcome - they're going to have a long wait."
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