"Network Rail are missing a golden opportunity to bring all their renewals contracts back in-house, and we will continue to campaign for that sensible goal," RMT general secretary Bob Crow said today.

"Simply re-shuffling some of the existing cards will still leave four privateers raking it in at the public's expense and subcontracting work to a dangerous muddle of subbies, agencies and one-man-and-a-dog outfits.

"Network Rail could make far greater efficiency savings and help re-establish a world-class safety culture by bringing all renewals contracts back under a single roof, as they already have with track maintenance.

"Our immediate concern will be to ensure that transfer of undertakings rules apply, and that there is no threat to our members' jobs, pay and conditions," Bob Crow said.