Griffiths will be appointed on the basis of a framework agreement, which will allow for incremental call-off of design and construction works.

The agreement will start on 14 September and will run for an initial term of 4 years extendable to up to 8 years.

The new open book partnering arrangement evolved from an original plan to appoint a design and build contractor during procurement.

The shift to a more flexible arrangement mid-procurement came after the council was told to relieve pollution levels after Portsmouth’s air quality was found to be worse than parts of London.

As a result of the Department for Environment, Food and Rural Affairs issuing an air quality enforcement notice, the redevelopment of the city centre and surrounding area road, highways and associated infrastructure is under review.

Future works will include highways construction and public realm improvements and public transport infrastructure.