The daughter of murdered MP Sir David Amess said he had been “catastrophically” failed by the Government’s Prevent program as he called for a full investigation into his death.

The veteran MP, 69, was stabbed by Ali Harbi Ali, then 26, at Belfairs Methodist Church in Leigh-on-Sea in Essex in October 2021.

Katie Amess, 39, said she was told Ali was reported to Prevent in 2014 but after a meeting his case was not followed up by the anti-radicalisation program “due to an administration error”.

She told the Sunday Times: “It has been reported. People were trying to help us and why was he allowed to go on and do whatever he wanted for seven years?

“What happened to my father should not have been an administrative error.”

Father-of-five Sir David was holding a surgery in his Southend West constituency when he was attacked by Ali, who was jailed for life in 2022 for the murder.

In an interview with the Sunday Times, Ms Amess, an actress who lives in West Hollywood in the United States, said the pain of his death was “unbearable” and “unspeakable”.

She added: “It’s quite obvious that Prevent is not fit for purpose, it has consistently failed people.

“I failed. It has failed my family catastrophically, it has failed the public and it has also failed other Members of Parliament.”

The Sunday Times reported that according to a coroner’s report published in July, Ali’s six-month review of Prevent’s case was “missed” and a 12-month review revealed “nothing of concern”.

Ms Amess said there had never been a “full public review of the events leading up to his death” after a coroner concluded the criminal trial was sufficient.

She added: “The people who could have actually helped me are nowhere to be seen, it feels like we’ve been completely ignored.

“My dad would be so shocked if he knew what we’re going through – he’d be ashamed.”

It was reported earlier this year that Ms Amess had taken legal action against Essex Police and the Home Office, bringing a personal injury claim to the High Court, as lawyers said she wanted to “ensure accountability and appropriate learning” from her father’s killing .

A Home Office spokesman said: “Our thoughts continue to be with the family and friends of Sir David Amess.

“The attack on Sir David Amess was a terrible tragedy, the safety of Members of Parliament is paramount and significant efforts have been made in response to his tragic killing.

“Prevention is a vital tool in preventing people from becoming terrorists or supporting terrorism and addresses all the ideological causes of terrorism.”

A spokesman for Essex Police said: “Sir David Amess was a serious public servant who worked tirelessly for his community.

“Immediately after his murder, two of our heroic unarmed officers faced the danger, desperately trying to save him and of course apprehending his killer.”

The force added: “We are aware that what is in fact a protection application form has been lodged with the court, however as these documents have not been passed to our force we cannot comment further on them.

“We remain committed to supporting our county elected officials in fulfilling their public duties and to that end we regularly review and advise on security measures for our Members of Parliament.”

Essex Police said that “as with all forces up and down the country”, they do not provide officers for policing operations in the constituencies.

Essex Coroner’s Service has been contacted for comment.