The mother of murdered soldier Lee Rigby said she was threatened with arrest unless she attended the appeal hearing of an internet troll who taunted her over his death.

Lyn Rigby said her treatment by authorities was “absurd and shocking” after she was summoned to a court hearing where a graphic image from her son’s murder featured as evidence.

Mrs Rigby said she was left “trembling from head to foot” when a photo of Islamic extremist Michael Adebolajo, covered in her son’s blood and brandishing a meat cleaver, was shown to the court.

“This has been one of the worst weeks since Lee died and it brought all the terrible emotions flooding back to me as if my son had been murdered all over again,” she told the Sunday People.

“I believe in our justice system because it put Lee’s killers behind bars but I don’t believe we should have been forced to court for this man.

“And to threaten us with prosecution if we didn’t attend was just absurd and shocking as well as deeply upsetting. It suggests that my grieving family has somehow done something wrong.”

Conspiracy theorist Christopher Spivey, a grandfather from Rochford, Essex, was convicted of harassing the Rigby family and sending grossly offensive messages over social media in 2015.

He had posted a series of comments on social media about the May 2013 killing in Woolwich, south-east London, including claims that the soldier had never existed and that the story of his murder was a conspiracy.

The troll also published the family’s home addresses and private photographs online and contacted the soldier's sister, Sarah McClure, claiming her husband, Rob, also a soldier, and Fusilier Rigby were the same person.

Spivey was eventually found guilty but escaped being sent to jail when a judge suspended his sentence.

After maintaining his innocence he launched an appeal, which was reportedly dismissed after a four-day hearing at Chelmsford Crown Court last week.

Mrs Rigby questioned why she and her daughter were made to attend the hearing via videolink from Bury Magistrates Court after they submitted witness statements.

“It’s horrific enough losing my son in such a violent way, but to listen to this man's twisted drivel was just heaping more misery on me,” she said.

Dave Hines, founder of the National Victims’ Association, criticised her treatment and ministers for failing those affected by crime.

“I feel for Mrs Rigby and the horrendous ordeal she has had to go through. It’s beyond comprehension, it’s completely outrageous and the public will be shocked.

“Families like this are let down by the system," he said.

A spokesman for the judiciary said: “Judges are acutely aware of the need to reduce as much as possible the painful ordeal witnesses have to go through in cases such as this one, and the option of video links means at least they don't have to attend court.

“But courts do have to balance that consideration with the need to ensure that justice is done.

“The legislation for an appeal from a magistrates’ court to the Crown Court, as this one was, requires that there is a re-hearing.

“This means that the prosecution has to call the evidence on which it relies – at the Crown Court – in order to prove the case against the accused, unless he is prepared to make admissions of fact.

“That is the only way that the witnesses whose account is an essential part of the case can be spared from giving their evidence a second time.”