A teenager broke his arm after falling 15ft from a fort.

James Smart, 15, of Overhill, Southwick, has been told he is lucky to be alive after the accident at old Shoreham Fort.

He had been out with friends when he lost his footing and fell onto concrete.

His father John, 50, said he was furious the Napoleonic Fort, which is the only one of its kind in the world, had been left to deteriorate.

He said the site was a meeting place for young people and something had to be done to either restore or make it safer before someone was more seriously injured.

He said: "We have been told it was only because James landed in the right way that he didn't die or suffer a more permanent disability.

"Imagine if it had been someone younger or he had fallen in a slightly different way.

"Something has to be done about the fort. It is always mobbed with kids and yet nothing has been done to make it safe.

"It should at least be fenced off or have barriers put up."

The accident happened at about 8pm on Thursday.

Campaigners have long fought to restore the historic site which was built in 1857 to protect the Shoreham port from French invasion.

Gary Baines, 26, from Durrington, Worthing, is such a fan of the monument he has set up a website about its history.

He said: "When I was a child, my grandfather took me to see this fort. I can remember running around the Carnot wall, holding a stick, pretending it was a gun.

"These days it is a very dangerous place for kids to play.

"It is part of our history and needs to be looked after. As far as I know it is the last fort of its kind in the country or even the world."

Rod Johnstone, chief executive of the Shoreham Port Authority, said because the fort was classified as "an ancient monument", English Heritage had to approve any work carried out to it.

He said the authority had been in talks with them for more than a year about how to improve safety at the fort but as yet no agreement had been reached.

Mr Johnstone said: "Things like handrails have to be thought about very carefully because of the historical nature of the monument.

"It is about balancing lots of issues.

"The only thing we can do to make the fort absolutely safe in the meantime is fence the whole thing off which would mean no-one could visit.

"We recognise the historical importance of the building and would not want to do this."

Do you think safety improvements should be carried out at the fort? Leave your comments below.