Flowers are placed in tribute to those who lost their lives in the attack at Westminster.

Police revealed the identity of the lone terrorist and last night the toll rose to five when an elderly man succumbed.

The Westminster terror attack has claimed its fourth innocent victim, as police confirmed that a 75-year-old man has died in hospital.

A Scotland Yard spokesman said: “The man had been receiving medical treatment in hospital following the attack and life support was withdrawn this evening.

“Next of kin have been informed and are receiving support from specially trained family liaison officers.”

The terrorist was named yesterday as Khalid Masood, a 52-year-old with a string of criminal convictions including possession of a knife. He was born Adrian Elms in Dartford, Kent and lived at various times in Rye, Crawley in West Sussex and Eastboune, in East Sussex.

The same man appears to have been convicted of a knife crime in 2003 in Eastbourne.

Detectives investigating his attack said they had arrested three women and five men on suspicion of preparing terrorist acts. The suspects were held in raids in London and Birmingham.

Scotland Yard said Masood was not the subject of any current investigations before Wednesday’s outrage and there was “no prior intelligence about his intent to mount a terrorist attack”.

However, he was known to police and MI5 and had convictions for assaults, including GBH, possession of offensive weapons and public order offences.

Masood was born in Kent on December 25 1964 and detectives believe he was most recently living in the West Midlands.

Three people were killed when the knife-wielding attacker drove a car through pedestrians on Westminster Bridge, before storming the Parliamentary estate. The terrorist was shot dead.

Prime Minister Theresa May disclosed Masood was once investigated in relation to concerns about violent extremism some years ago, but was a “peripheral figure”.

Police and intelligence agencies have mounted a massive investigation to piece together the killer’s movements in the lead-up to the attack.

Searches were carried out at three addresses in Birmingham and one each in east London, Brighton, south east London and Carmarthenshire.

The identities of the victims have emerged, one a US tourist from Utah celebrating his wedding anniversary, the other a “highly regarded and loved” member of college staff.

Kurt Cochran and his wife, Melissa, on the last day of a trip celebrating their 25th anniversary, were visiting her parents in London. Mrs Cochran was badly injured.

Aysha Frade, who worked in administration at DLD College London, in Westminster, is understood to have been 43 and married with two daughters. She was believed to be on her way to collect her children when she was killed. Four people were still critical last night.

Meanwhile, a fund set up for the family of murdered hero PC Keith Palmer had surged past £340,000 late last night

Picture: PA. Police forensic officers search Parliament Square the day after the terrorist attack. Eight people have been arrested in raids by police and intelligence agencies in connection with the atrocity.

Picture: PA. Above: Kurt Cochran and wife Melissa, from Utah, were on a trip to London to celebrate their 25th wedding anniversary. Mr Cochran was killed in the terrorist attack. His wife was badly injured.