He wasn't killed in action - he was shot by his own side for desertion and branded a coward.

The records of his court martial show that the 19-year-old fled terrified after a particularly heavy bombardment.

His niece Doris Conroy now wants justice for Charlie and is backing calls in the Scottish Parliament to have him and hundreds like him pardoned.

Charlie Nicholson: Fled after heavy bombardment

She told the BBC: "I just want something to come out of this to give peace to the families.

"It is a terrible thing to think that your relative was a coward."

There were 306 executions for cowardice and desertion during WWI.

Last year the UK government said it would scrap the death penalty for military offences in the armed forces.

But Labour MSP Elaine Murray says that is not enough.

The BBC's Liz McKean reports on anguish of relatives calling for a pardon

She said: "The young men at the Western Front were operating under constant and extreme physical and psychological stress. Their actions were determined by the stress they were under, rather than a desire to let down their country."

She added: "They were not convicted at normal courts, they were wartime courts with summary justice.

"The people that convicted them were also living in appalling conditions and it is quite possible that the judgements were unsound."

But Conservative MSP and former Scots Guards officer Ben Wallace said: "These men were judged at the time by their peers and it is a dangerous precedent to pick 307 people for a pardon.

"We should be remembering all the horrors that existed in WWI and leave it at that.

"This is history we are tinkering with. The crime of desertion is serious, but we cannot judge the severity of the punishment by our values.

"Do we pardon those that were flogged by Lord Nelson?"

Soldiers were shot after a court martial

The forces have not carried out the death penalty for more than 70 years, but it still applies to five offences: misconduct in action, assisting the enemy, obstructing operations with intent to assist the enemy, mutiny and failure to suppress mutiny with intent to assist the enemy.

It was last used in 1920 when Private James Daly, of the 1st Battalion of the Connaught Rangers was found guilty of mutiny at Jullunder in the Punjab.

Most WWI executions did not relate to these five offences, but to other offences such as desertion and cowardice which have long since disappeared from the Army's statute book.

Meanwhile, the families of relatives those that deserted in WWI are still awaiting a pardon.

Tom Stones, 58, of Stafford, whose great-uncle Sergeant Joseph Stones, 25, was shot in January 1917 for cowardice, said he would not rest until he achieved a pardon for him.

He said: "This is a clear case of total injustice".

In his statement to the court martial on Christmas Eve 1916, Sergeant Stones, of the Durham Light Infantry, told how his unit was ambushed.

Sergeant Stones jammed his rifle across the trench to stop the Germans advancing while he ran back to raise the alarm.

As he ran back, he was said to have collapsed. He was taken to hospital and arrested the next day. He went in front of a firing squad on 13 January 1917.

Last year his name was added to the war memorial in his home town of Crook, County Durham, due to the strength of feeling in the area.