Part of the 400-year-old Antrim Castle has collapsed, it was revealed today, after a 40ft section of the gate at the former estate crumbled last night.
Market Square and the war memorial were covered in fallen rocks, and multi-million pound National Lottery restoration scheme has been affected.
Cllr Adrian Watson said: “It is a major local landmark and we carried out some restoration work of the gate and castle battlements five or six years ago. This is a huge blow.”
He added the reason for the subsidence was a mystery.
Northern Ireland football fans on their way to the pub to watch the match noticed the slippage, but nobody was hurt.
The castle was built in the Plantation era and belonged to local landowner Lord Massereene. It was erected in stages between 1610 and 1666. Destroyed by fire in 1922, it was demolished in the 1970s.
The remains of the castle, chiefly its Barbican Gate, and gardens had been marketed as a tourist attraction and a National Lottery grant worth around £4m was due over the next few months, Mr Watson added.
The area has been sealed off as the remaining segment may be unsafe.
PA