A fire that destroyed a former convent in Downpatrick, County Down, was started deliberately, the Northern Ireland Fire and Rescue Service has said.

The blaze was reported shortly after 7pm on Sunday at the former Convent of Mercy in the Stream Street area. At its height, 70 firefighters and 10 appliances from stations including Newcastle, Dromore and Newtownards were involved, along with two aerial ladder platforms, a command support unit and a water tanker.

Firefighting operations concluded at 7am on Monday. The NIFRS stated the cause is believed to be deliberate.

The building, which dates from the 1870s and is listed, had been vacant and was on the market with planning permission for 39 flats aimed at older residents. It went on sale last October with an asking price of £400,000, having previously sold for £175,000 in 2019.

SDLP South Down MLA Colin McGrath said the convent was a well-known landmark. He thanked firefighters and emergency crews for their quick response and expressed sympathy for nearby residents.

SDLP councillor Conor Galbraith noted the fire appeared confined to the roof, which had collapsed. Sinn Féin councillor Oonagh Hanlon appealed to the public to avoid the area to allow emergency services to work safely. Police also asked people to keep their windows and doors closed because of smoke.