National Grid Transco this week boosted contractors Balfour Beatty, Amec, Morgan Sindall, Skanska and McNicholas by placing orders for a £1.6bn gas replacement works programme.
The contracts are part of a 30-year plan to replace Victorian gas mains with modern pipework.
Transco has handed Balfour Beatty a £380m contract for work in the Manchester area; Amec has taken on £280m of work along the M1 corridor between Sheffield and Leicester; Morgan Sindall has been appointed on a £320m contract in the West Midlands; and Skanska and McNicholas have been appointed to complete £400m of work in north London.
All contracts are for an initial period of eight years, with the possibility of a five-year extension.
Work, which starts in April, involves design, management and construction.