A series of threatening phone calls made to Sir David Amess’ adult son on the evening before the MP’s murder were “in no way linked” to the attack, police said.

Katie Amess, the veteran politician’s daughter, called for a full investigation into his death and said there were still unanswered questions.

He told Radio 4’s Today Programme: “The night before what happened to my dad, my brother got a phone call saying my dad was going to be killed.

“He immediately informed the police.

“Frankly, given that there was a death threat against an MP, you would assume they would turn up the next day to protect him.

“The man who killed my father admitted that he went to another operating room or other people’s homes to kill them and that he did not openly commit the attack when he saw the police presence.

“If the police had been there, we might not be sitting here today without my father.”

In a statement, Essex Police said police were contacted at around 9pm on 14 October 2021 “following reports of threats against a man in his 30s”.

“We immediately launched an investigation and a woman in her 20s and a man in his 30s, both from Southend, were arrested,” said Essex Police.

It was stated that “This incident and the murder of Sir David are not connected in any way, the arrested persons and the person to whom the threat was directly directed know each other, and none of them have any connection with Ali Harbi Ali.”

Sir David, 69, was stabbed to death by Ali Harbi Ali at Belfairs Methodist Church in Leigh-on-Sea, Essex, on October 15, 2021.

The father-of-five was attacked during surgery in his Southend West constituency by Ali, who is sentenced to life imprisonment for murder in 2022.

“The police then told us that they had arrested the people who made the phone call and that was irrelevant, but that was irrelevant to us because they needed to stay put,” Katie Amess told Today.

“One threat should be enough for you to go and protect someone,” he said.

“If they had been there my father probably wouldn’t have died and I think we need to do a full investigation into why they didn’t show up.”

Essex’s senior coroner, Lincoln Brookes, touched on the issue of threats made to Sir David’s son in his 18-page decision not to proceed with the inquest into Sir David’s death.

He said Sir David’s adult son, also named David Amess, called Essex Police and “told them he had received a number of threatening phone calls”.

The coroner said documents provided to him by police “show that threats made by Mr Amess on the evening before Sir David’s death were taken seriously and action was taken by the police”.

He said the investigation into the searches after the murder was ongoing and “it was determined that this was a completely unrelated incident.”

Mr Brookes said the calls “were not a threat to Sir David’s life” and that the circumstances described did not show “an arguable breach of either a systemic or operational duty in relation to a murder committed by an unrelated person in unrelated circumstances”.

He wrote: “The evidence I have received does not enable me to say that there was unquestionably a point in time at which the authorities should have appreciated the real and immediate risk that the perpetrator would carry out and carry out an attack on Sir David or any MP.” Potentially effective action to prevent this.

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

“Immediately after his murder, our two heroic unarmed police officers faced danger, desperately tried to save him and, of course, detained his killer.

“Several of our other officers joined shortly afterwards and worked with paramedics to help save Sir David, unfortunately they were unable to do so.

“In the days and months since then, our team has worked around the clock to reassure the community and support our colleagues at the Metropolitan Police Counter Terrorism Command to do all we can to help deliver justice.

“We are aware that, in fact, the protective request form has been submitted to the court, but as these documents have not been served to us, we cannot comment further on them.”

The spokesman added: “We are committed to supporting our elected members across the county in carrying out their public duties and to this end we regularly review and provide advice on security arrangements for our Members of Parliament.

“Sir David and the Amess family are still in our thoughts.

“We were contacted at around 9pm on Thursday 14 October following reports of threats against a man in his 30s.

“We immediately launched an investigation and a woman in her 20s and a man in his 30s, both from Southend, were arrested.

“It was stated that this incident and the murder of Sir David are not linked in any way, that the arrested persons and the person to whom the threat was directly directed know each other and that none of them have any connection with Ali Harbi Ali.

“We take the safety and security of all our residents, including elected members, extremely seriously.

“Like all forces across the country, Essex Police does not provide officers to MPs’ constituency surgeries.”

They said: “If information or intelligence comes to light that would give us concern about the safety of an MP, we would of course advise and guide them to keep them safe and provide a police presence where necessary.

“Following Sir David’s murder, the National Police Chiefs’ Council asked all Chief Constables to contact their MPs to discuss their safety.

“Our Police Chief BJ Harrington did this at the time and is in regular dialogue with our lawmakers as well as our local police commanders.

“More broadly, Essex Police is part of a nationwide police protection security program designed to give MPs access to extra security in their homes and constituency offices; the program was established in 2016 following the murder of Labor MP Jo Cox.”