The death of psychotic Matt Groom was partly caused by failures at Whittington Hospital, an inquest heard today.

Coroner Mary Hassell has now ordered the Archway hospital to outline actions it will take. She said: “There is a risk that future deaths will occur unless action is taken.”

On June 15, the same day criminal solicitor Mr Groom was admitted to Whittington for mental health issues, the 36-year-old died after standing in front of a lorry on the M11 near Debden.

Ms Hassell, who last Wednesday ruled out suicide because he was psychotic, gave her verdict at St Pancras Coroners Court this morning.

She said three factors prevented Mr Groom from receiving life-saving treatment:

A six-and-a-half hour wait for a mental health assessment in the hospital

Mr Groom, who believed he was being watched by the National Security Agency and claimed he crashed the stock market, was admitted at 1.35pm.

He became increasingly agitated as he waited through the day, pleading to be sectioned and threatening violence.

An assessment finally started at 7.55pm, but walked out at 8.23pm.

A lack of recognition by those assessing Mr Groom – mental health nurse Joyce Tano and psychiatrist Neil Sheehan – that his abrupt departure warranted emergency action from security colleagues and police

Dr Sheehan believed he needed to be sectioned. He tried to persuade Mr Groom to come back, but at 8.29pm slipped off his shoes and ran.

He was chased by his uncle, John Groom, and persuaded to return at 8.40pm. But two minutes later, Mr Groom said he would not stay, and the two walked out again.

Ms Tano called police at 8.51pm. Meanwhile, John was having difficulty calming Mr Groom down, who ran off a train at Debden.

At 10.49pm, he stood in front of a lorry at nearby Junction 5 with his arms aloft. The lorry was unable to avoid him and he died at the scene.

Mr Groom’s fluctuation between psychosis and calm and reasonable demeanour

While waiting for his mental health assessment, Mr Groom shouted that he would punch someone and that he may as well kill himself. But at other times, he was calm.

Dr Sheehan had assessed that Mr Groom was not of immediate risk to himself or others.

Ms Hassell has now sent a prevention of future death report to Whittington, as well as Camden & Islington NHS Foundation Trust, which provides mental health staff. Both must respond by January 11.

More to follow.