The wall currently acts as a partition between a Leconfield Estate cottage and the old magistrates court car park. But its future is threatened by plans to demolish the old courthouse and build new homes.

The wall originally formed part of a solitary confinement cell in Petworth's notorious House of Correction which stood on the site from l789 to 1881.

Chairman of Petworth Society Peter Jerrome said: "This is an important part of the history of the town, you can't just go knocking down Petworth's heritage, so our first priority was to stop someone knocking it down."

"The house of correction was the major prison of West Sussex," he said "and reflects the time when Petworth was the second most important town in West Sussex. The prison was known for being very austere."

From the early l820s to the late l830s the governor was John Manse renowned for his severe treatment of prisoners.

"Mr Manse was extremely austere, but also very religious and he believed it was his religious duty to stop prisoners reoffending and believed he was performing God's work.

"There was a rule of silence," said Mr Jerrome, "and even the warders had to wear soft shoes, the idea being that younger prisoners would not be influenced by the old lags."

"As I understand it, when these prisoners were in solitary confinement they scratched their names, initials and dates on the bricks of the cells."

In l881 the prison was demolished, but the bricks with the initials engraved on them, were used to build the wall outside the magistrates court.

Plans by developers currently show the wall preserved, but inside the boundary of a new private house.

"If it is going to be in a private garden, we need guarantees that it will be looked after," said Mr Jerrome, "but it really needs to be accessible to the public and so this is not a particularly satisfactory solution. But if someone knocks it down we have lost a serious piece of Petworth history."

Petworth Parish Council has led the fight to save the wall. Its chairman Andrew Howard told the Observer: "We have objected to the development plans on parking grounds and also feel it is inappropriate to leave this historic wall inaccessible to the public in a private garden. We have suggested a modification which would give the public access to the wall."

Mr Howard told the Observer: "On a personal note two of my ancestors were imprisoned in Petworth jail in l843 when they were just children for three months hard labour after running away from Chichester workhouse wearing workhouse clothing."