A memorial to Army personnel killed during a Second World War friendly fire incident on Salisbury Plain will be unveiled in Warminster Garrison Church on Friday.

The event marks the 70th anniversary of the 1942 tragedy, in which a Hurricane pilot opened fire on spectators at a military demo in Imber, killing 25 and injuring 71.

Wiltshire Historical Military Society has funded a memorial to the dead, which will be unveiled by the Lord Lieutenant of Wiltshire Sarah Troughton at the Garrison Church, Imber Road, at 11am.

Society secretary Rod Priddle said: "Our role at the society is to ensure these events are remembered and properly commemorated at sites of historical importance.

"This incident is not very well documented as it would have been hushed up at the time for morale. The families of the victims were told a cover story and the truth only emerged later.

"We are hoping to have a good number of people along for the memorial service.

"We wanted to put it at the scene of the accident, but that is a restricted area now."

The tragedy occurred during a tactical air demonstration of fighter aircraft making low-level attacks on dummy soldiers and stationary army vehicles.

On the day of the demo the weather over the target was fine but hazy, making visibility poor when looking into the sun.

The exercise was led by Spitfires of No. 234 Sqn, which made their pass without firing. They were followed by the six Hurricanes of No. 175 Sqn.

The first five of these engaged the target area, but the pilot of the sixth aircraft mistook the spectators for the target and opened fire on his approach.

Three days after the tragedy Prime Minister Winston Churchill visited to witness a similar demonstration.

The 20-year-old American pilot was shot down over France during a night time raid only a few weeks later.

Mr Priddle added: "There were a number of factors which contributed to the incident, but no one was blamed, and the pilot wasn’t demoted or taken off flying. I think they needed every pilot they had."

The roads through Imber village are expected to be open next between June 2-5.