Jack Merritt's father says it's a 'shame' to have to sue the Government

The father of terror attack victim Jack Merritt has called it a "shame and unnecessary" to have issued proceedings against the Government over his son's death.

A lawyer for the family said they filed a High Court claim against the Ministry of Justice and the Home Office after the two government departments failed to agree to a delay to any legal action until all investigations are completed, including the inquest.

Jack who was 25, was fatally stabbed along with Saskia Jones, 23, by convicted terrorist Usman Khan during a prisoner rehabilitation event at Fishmongers' Hall in London on November 29 last year.

Khan, 28, was out on licence when he attended the event near London Bridge, organised by Cambridge University's Learning Together programme.

He was armed with two kitchen knives and wearing a fake suicide vest.

He was tackled by members of the public with a narwhal tusk, a decorative pike and a fire extinguisher before he was shot dead by police on London Bridge.

Solicitor Kate Maynard said the family, including Jack's mother, Anne, his brother, Joe, and his girlfriend, Leanne O'Brien, had been left with "no alternative" but to issue proceedings.

In a series of tweets on Thursday, Mr Merritt said: "We have issued proceedings against the Home Office and Ministry of Justice because they refused to agree to an extension to the claim window.

"You have to issue proceedings ... within a year of the incident because after that you lose right to sue should you subsequently want to following findings of an inquest for example."

He said every interested party had agreed to an extension, except for the Ministry of Justice and Home Office, adding: "Which is a shame and unnecessary, and not what we want to be doing on the anniversary of our son's death."

A Home Office spokeswoman says their thoughts remain with the families and friends of Saskia Jones and Jack Merritt following the terrible attack.