EXPERTS are to carry out urgent repairs to a tower on York's historic city walls which has begun to bulge and crack.

City of York Council, which manages the city walls, says the condition of Tower Two, near Baile Hill, has deteriorated over the last five years.

"The condition has begun to worsen faster than expected," a spokesperson said. "This section of the walls remains safe, but work is needed swiftly to stop further deterioration."

The work is due to begin on October 7, and is expected to last at least four months.

Tower Two, thought to have been built in the mid-fourteenth century, is on the walls between Baile Hill (the remains of a motte and bailey castle) and Bitchdaughter Tower. Experts say it was probably built as an addition to the city walls - with the walkway we use today only added much later, in the 18th or 19th century. It is the 'infill' of rubble used when the walkway was built that seems to be causing the problems.

"Archaeological and structural investigations have determined that the weight of the tower’s causing the damage," the council says. "Excavating the infill material will help stabilise the tower but masonry repairs and structural supports will also be required."

Repair work will take place on weekdays between 8am and 3.30pm from October 7 onwards.

The walls will not need to be closed. A works area will be set up at the bottom of the walls rampart at Baile Hill Terrace. "Pedestrian access to the ramparts will be maintained, but space will be reduced," a council spokesperson said.

The restoration work will be part of the city walls capital programme supported by Historic England. Archaeologists see it as a chance to find out more about the tower.

“Walking the city walls is so popular that it will be a surprise to many people that they were never designed to have this kind of walkway - or that sections of the walls were filled in to create the path," said Ian Milsted of York Archaeological Trust. "This will be the first time in 200 years that the inside of this tower will be exposed.”

From October half-term, visitors will be able to book free tickets to see the work. Find out more here