A major project that will ultimately see Norwich Castle's medieval keep restored to its former glory is facing a huge increase in costs as it nears completion.

The scheme, initially expected to cost about £20m, has now risen to £27.5m, requiring Norfolk County Council to allocate further funds to support the revamp.

It means an extra £4.7m is required, following earlier boosts to the budget.

This comes amid a final push to complete the regeneration of the Norman landmark, which is now expected to be completed by February 2025 with a phased reopening of spaces from Spring 2025.

Norwich Evening News: The battlements at Norwich Castle will be fully accessibleThe battlements at Norwich Castle will be fully accessible (Image: Feilden + Mawson)

According to a report to cabinet members, there have been several significant challenges to overcome throughout the construction project.

This includes the unexpected discovery of hidden Norman and Victorian features, plus the need to replace a leaking roof, which has set back the schedule for the full reopening of the 900-year-old building.

A new bridge at Norwich Castle will lead visitors into the keepA new bridge at Norwich Castle will lead visitors into the keep (Image: Denise Bradley)

Costs have also escalated due to the project being affected by the Covid pandemic and difficulties obtaining steel because of the war in Ukraine.

NCC plans to fund the increased costs by using money already budgeted for growth, investment and highways projects.

Norwich Evening News: Norwich CastleNorwich Castle (Image: Norfolk Museums Service)

It will redirect £2.75m from money intended to be used to support the development of an energy park in Great Yarmouth. That facility has not yet been developed in any way so far.

The remaining £1.99m will be removed from funding for highways projects.

This could mean road improvement schemes may need to be deferred due to the loss of cash earmarked for such works.

Councillor Andrew Jamieson, deputy leader and cabinet member for finance at Norfolk County Council, said: "We expect this project’s impact to go far beyond the walls of the keep.

"The reborn castle will draw in visitors from around the world, bolstering the reputation of Norfolk’s culture and heritage for decades to come.”

Norwich Evening News: How the revamped Great Hall in Norwich's Castle Keep could lookHow the revamped Great Hall in Norwich's Castle Keep could look (Image: Haley Sharpe Design)

The majority of the funding for the project has come from the National Lottery Heritage Fund and NCC, along with other national and local grants and public donations.

Cabinet members will be asked to approve the £4.7m increase to the budget on Monday November 4.