French utility EDF has asked bidders to tender for the third time for the same £180m earthworks and preliminary works package at the Hinkley nuclear power station in Somerset

EDF initially tendered the job, then worth about £100m, in March, before expanding and re-tendering it in May. A source said in the latest round EDF had asked all bidders to bid against ideas generated in the previous tenders.

Despite the changes, at least three consortiums - Balfour Beatty and Vinci; Costain and Sir Robert McAlpine; and Kier, URS and Bam Nuttall - are thought to still be in the running.

Contracting consortiums are concerned there is no prospect of regaining potentially millions in bid costs. The source said: “If this is the level of change on the preliminary contract, what on earth is the main contract going to be like?”

EDF has just separately tendered a contract for almost 9km of giant tunnels at the plant. Morgan Est is to join Balfour Beatty and Vinci to bid for the work, with Kier and Bam Nuttall joining with Wayss & Freytag. The Costain and Sir Robert McAlpine consortium will also bid.

Kier and Bam Nuttall have won the first contract for the plant, thought to be worth about £3m, to build fencing and secure the site.