A SEALED-UP medieval doorway at Lincoln Castle is to be knocked through under plans to create uninterrupted wall walks.

Lincolnshire County Council has £3.5 million to open up the south wall to the public, linking it to the other three walls via a system of cantilevered bridges and timber walkways.

Work is set to begin on the wall, off Drury Lane, in May.

It is part of a wider regeneration and repair project and creating the complete circuit of the walls will need further work in 2012 and 2013.

Visitors currently enter Lucy Tower – the medieval castle keep used as a graveyard for executed prisoners in the 19th century – via steps in the six o'clock position.

The aim is to open a blocked up doorway on the west side of the tower – discovered by archaeologists – for access.

Once inside the tower, people would exit via the existing doorway and follow a new walkway around the exterior tower wall to get back on to the south wall at the nine o'clock position.

New access is proposed onto the south wall from the south west corner and from the south east corner into the Observatory Tower.

The county council's tourism development manager Mary Powell said: "One of the best ways to create access where there hasn't been access is by using cantilever walkways.

"We did some archaeology which showed there was a doorway on the west side of Lucy Tower which will be knocked through.

"This was possibly blocked up during Victorian times.

"What we cannot do is knock through the medieval wall on the other side of Lucy Tower so the plan is to go out of the existing door and around it to get back on to the south wall.

"The net effect will be that visitors will no longer need to visit the castle in two stages – the walls and the Lucy Tower.

"It will be a complete circuit which will greatly improve the visitor experience."

The wider regeneration project offers a new lift and disabled access at the east gate.

Brian Harding, 63, who used to organise a classic vehicle rally at the castle, said a single circular walk made sense.

"Anything that can be done to improve the castle for visitors is good for tourism and I think this idea of joining up the wall walks is brilliant," said Mr Harding, of Shearwater Close, Hartsholme.

"Tourism brings money and if Lincoln gets more tourists visiting an improved attraction, that can only be good for the city."