Two huge cannon from a historic Donegal naval base have been found buried at a former Londonderry military barracks.

The cannon are believed to pre-date partition in Ireland and would have been used by the Army at Fort Dunree near Buncrana as a coastal defence.

One of the cannon weighs five tonnes while the second weighs a mammoth 19.6 tonnes.

They were uncovered during the excavation of the parade ground at the former Ebrington Barracks, which will open on St Valentine’s Day as Derry’s second major outdoor arena.

Both weapons dwarf the other famous historic cannon in the city which were used during the Siege of Derry and now sit on the city walls across the river.

The smaller one has been identified as an Army breach loading Mark 6, which had a firing range of 9km.

The large cannon is still being authenticated but is believed to be a breach loading Mark 7, which has a range of 14.5km.

Alan Armstrong, Ebrington development director with regeneration company Ilex, said the cannons could be displayed in the city’s Maritime Museum.

Describing how they came upon the cannon, Mr Armstrong said: “When we were clearing out Ebrington Square there was a serious bit of excavation required to make the walkway and we just discovered the first one.

“These cannon, when|they were made, went to the Royal Navy first and then later were passed on to coastal defence and then went to the Army.

“We think this might have come from Fort Dunree — there was a lot of defence around the Swilly up until partition.

“This smaller cannon was introduced in 1894 and decommissioned in 1922.

“We think it might have moved from Fort Dunree to Ebrington at around 1912.”