Police forensic teams search second Surrey property after arrest of second man over Parsons Green Tube attack

Raided house linked to 21-year-old man arrested in Hounslow

Police had earlier searched a property in Sunbury-on-Thames, Surrey (REUTERS)

Police are searching a second house in Surrey as part of their investigation into the Parsons Green Tube bombing.

It comes after a second man was arrested in relation to the attack, which left 30 people injured when the device partially exploded on a District Line train on Friday morning.

An 18-year-old suspect was detained at the Port of Dover on Saturday morning and officers later apprehended a 21-year-old man in Hounslow, west London, at 11.50pm. Both were held under the Terrorism Act.

Police forensic teams were searching a house in Stanwell, Surrey, on Sunday in connection to the second arrest.

Officers have cordoned off a terraced property in the neighbourhood, which lies just outside of Hounslow, close to Heathrow Airport.

Police were also continuing a search in Sunbury-on-Thames, Surrey, at the home of foster care couple Penelope and Ronald Jones.

The elderly couple, who received MBEs for their services to children and families, provided a home to the teenager who was arrested in Dover on Saturday.

They are also connected to a registered resident of the Stanwell property being searched by police, sources told Sky News.

There is no suggestion the couple are involved in the investigation.

The couple were said to be staying with friends for at least the next five days following the police raids, during which surrounding houses were evacuated by counter-terror officers, with residents told they had “one minute” to flee their homes.

Homes neighbouring the searched property in Stanwell were not evacuated following the second raid in the early hours of Sunday morning.

Tony Kuylenberg, who lives in the road, told Sky News: "We heard some loud shouting coming from outside. We didn't bother to look, we just thought it was someone coming back from the local pub.

"I opened the door this morning, looked out the window and saw a police van. First of all I just thought it was a couple of police officers who had gone round to arrest someone but then I see seven or eight police officers all pile out of a police van. Then there was all the undercover plan police covers turning up. Every 10 minutes another car was turning up."

A Surrey Police spokesman said: "We can confirm that a search is taking place at a residential address in Stanwell, in connection with the arrest in Hounslow. We are supporting the Metropolitan Police with ongoing enquiries.

"There is increased police activity in the area but no local evacuation will take place."

The second arrest came after Metropolitan Police Deputy Assistant Commissioner Neil Basu said investigators were "keeping an open mind" over whether more than one person was involved in the terror plot.

“If there are other people responsible it’s our job to find them and that is part of the reason that we are remaining at critical threat," he said before the UK's terror threat level was reduced to "severe" on Sunday.

The threat level had been increased to "critical" in the wake of Friday's attack, in which 30 people were injured when the improvised device exploded during rush hour at Parsons Green station.

All but one of those injured in the explosion have been discharged from hospital, NHS England said.

Police have since identified 121 witnesses, of whom 100 have been spoken to, Mr Basu said.

Announcing the downgrade of the threat level, Home Secretary Amber Rudd said police had made "good progress" with their investigation.

Soldiers who had been drafted in to guard public sites in order to free up police resources will "return to their original positions" over the next few days, Ms Rudd said.