Rok and Galliford Try are the latest construction companies to be investigated by the Office of Fair Trading

Galliford Try has admitted that is being investigated by the Office of Fair Trading over tenders submitted between 2000 and 2005.

The news follows housebuilder ROK's announcement this morning that two of its subsidiaries were also being investigated.

A Galliford Try statement said that the tenders related to its Building Division. It said that the tenders related to a very small proportion of the division's bidding activity during that period.

The housebuilder was the second company to admit it was being investigated in the past week. Kier announced on Friday it had been contacted by the OFT.

The OFT investigation into the construction industry has been running for more than two years and has seen 57 offices raided by inspectors. The investigation is looking into cover pricing in the industry, but it is not known whether it is confined to a particular sector or area of the country.

A Rok statement read: “Two subsidiaries within the group have received notices from the OFT regarding its investigation, in respect of a small number of tenders which related to periods prior to their acquisition by Rok. Appropriate warranties and indemnities were obtained at the time of the respective acquisitions and both subsidiaries are cooperating fully with the OFT in their investigation.”

Any business found to have been partaking in cartel activity can be fined up to 10% of their global turnover, and in extreme cases directors can face up to five years in jail.