The cause of the artillery shell which strayed five miles off course and exploded in a farmer’s field in Patney, near Devizes, was due to the charge being too big, the Army has told the Gazette.
The shell was fired from a 105 Light Gun on the south of Salisbury Plain military training area but the wrong charge meant the shell went further than it should have done.
The shell exploded in farmer Andrew Snook’s field leaving a 6ft by 6ft crater and was about 300 metres from the Paddington to Penzance railway line. No one was injured.
An Army spokesman said: “When the artillery shell was fired it was going in the right direction and it should have landed in the Salisbury Plain impact area but the charge was too big and it sent the shell beyond the intended target.
"The initial findings of the investigation are it was caused by human error.
"There is still a final report to be written and anyone found to have fallen short of the standards of the British Army will be dealt with in an appropriate manner.”
As a result of the error the Army have introduced two additional safeguards.
These are an extra person – a senior gunnery instructor – will be present and overseeing procedures when live firing takes place and further checks, both visual and paperwork checks, will be carried out on the charge bags which are loaded into the guns.
The Army spokesman said: “The safety of our personnel and the general public is our priority in all training.
"These additional safeguards will be standard practice from now on and are being introduced to our existing safety procedures to help ensure this does not happen again.
Four senior Army officers met members of Patney Parish Council yesterday to explain the results of the investigation and also apologised.
The stray shell exploded in Mr Snook’s field last Wednesday but the crater was not found until two days later by Mr Snook. He informed the Army and live firing was suspended at 3.20pm on March 7.
Live firing can now resume on Salisbury Plain.