A mental health patient who pushed a finance expert in front of a London Tube train one day after being released from hospital has been locked up indefinitely.

Former Royal Mail worker Alan Alencar, from Edinburgh, pushed Alain Lesjongard on to the tracks and then calmly tried to leave by mingling in with horrified commuters rushing for the exit.

Mr Lesjongard, 55, survived "by an extraordinary stroke of luck" as he curled up in a foetal position between the live rails at Bayswater station on the District Line.

The compliance executive managed to crawl back on to the platform with his suit in shreds despite suffering a broken leg, a fractured spine and a deep cut to the back of the head.

He told police he "feels lucky to be alive" but has been unable to visit the stretch of the London Underground since the attack on 2 November last year and suffered a panic attack when he thought he saw Alencar in the street.

Alencar, 29, has been suffering from mental health problems since 2012 and was diagnosed with probably schizophrenia in 2015 while he was living in Edinburgh.

He was admitted to hospital in April 2017 and prescribed with anti-psychotic drugs but was being "prepared for discharge" to his own flat in Northcote Street.

On 1 November he was given unescorted leave for five days and decided to travel down to London to visit his mother.

He was returning from seeing her when he got off a Circle Line train at Bayswater and sat on a bench at around 5pm.

Around a minute later Mr Lesjongard, who has previously worked as head of international compliance for the US bank BNY Mellon, walked on to the platform intending to catch a westbound District Line train.

CCTV footage shows Alencar sitting on a bench just metres away from Mr Lesjongard before the attack.

Prosecutor Alex Agbamu said: "Just before the train came into the station he rose from the seats and gave Mr Lesjongard a hard push from behind, sending him into the path of the oncoming train.

"The train driver Maria-Victoria Kakar immediately applied the emergency brake which brought the train to a halt about three quarters of the way down the platform, passing over Mr Lesjongard as he lay curled between the tracks."

He continued: "By an extraordinary stroke of luck Mr Lesjongard not only avoided touching the live rails he avoided any significant impact with the train.

"Members of staff on the platform were astonished to see Mr Lesjongard crawl out from under the train and heave himself onto the platform.

"His suit was in shreds and he was in a state of shock."

Mr Lesjongard was heard to say that he thought he was dying.

Alencar was arrested in the ticket hall after he was spotted by a member of staff and was described as having a "wide eyed stare and a vacant expression".

After being told the victim might have died, he replied: "First time for everything, but I won't do that again" and "I was crazy and stupid but I won't do it again."

Train driver Mrs Kakar, who has a two-year-old son, has been unable to work sicne the incident.

Mr Lesjongard, a father-of-two, still suffers from pain as a result of his injuries.

Alencar has previous conviction for breaching a non-molestation order relating to his father and a public order offence.

His barrister Andrew Forsyth said his client wanted to apologise to Mr Lesjongard and his family.

He said: "This is not an incident that would have happened but for the serious illness from which he suffered at the time."

A doctor described Alencar as "living in another world for years" and "detached from reality".

Judge Sarah Munro QC detained Alencar indefinitely under sections 37 and 41 of the Mental Health Act at Springfield Hospital in southwest London.

She told him: "Miraculously Mr Lesjongard was not killed in this incident. He rightly feels lucky to be alive.

"He was a complete stranger to you. I am quite satisfied you are suffering from a severe and enduring mental illness.

"A hospital order is the most suitable method of dealing with this case. The risk to the public cannot be managed in prison."

Alencar, of Northcote Street, Dalry, Edinburgh, admitted attempted murder at a previous hearing.