Previously hidden, unexpected and severe corrosion on a critical section of the structure was discovered by contractors carrying out repairs in January this year.

The severe corrosion was revealed when sections of concrete were removed from the hanger bars, which support the main trusses of the 200-year-old bridge.

The bars are not commonly found in bridges and the engineering solution to repair the unique hanger bars, which would allow the bridge to fully reopen, is proving a technical challenge without radically altering the Grade II* structure.

Engineers are now assessing an option for installing putting a bearing under the truss to support the weight of the bridge, but this needs detailed assessment because it will alter other load paths on the abutments and bridge.

The change of load path can cause structural elements to act differently and these are sensitive to change because of the bridge’s age and design.

Careful detailed assessment and computer modelling is now progressing to find out if the bearing is a feasible option which will then inform the next steps for the repairs and this is anticipated in May.

This has not stopped other works which are continuing with main concrete repairs to the deck and trusses and these are expected to be completed within the coming weeks.