NEPO was forced to rip up previous bids after legal advice warned the whole award process was vulnerable to challenges from failed bidders.

Prequal submissions from more than 80 firms were received way back in April 2011 with around 40 moving to the more detailed evaluation and award process.

But procurement chiefs said big variations in pricing schedules submitted by contractors made the whole process difficult to evaluate, despite many attempts to clarify bids.

The categories have now been divided between construction-only and design and build capability, rather than by regions as attempted before.

The lots are also divided between projects valued above or below £4m.

For the larger packages Graham Construction will not cover design and build, while Miller is on the panel for only design and build work.

Councils in the north east hope to make big savings and reduce the time to market for appointing contractors, saving £35m over the four-year term on new building work in the region.