Undated handout photo issued by the Metropolitan Police of Daniel Abed Khalife. AP

Britain's Metropolitan Police said on Saturday there had been more confirmed sightings overnight in the Chiswick district of London of a former British soldier suspected of terrorism offences who escaped from prison.

Daniel Abed Khalife, 21, absconded from London's HMP Wandsworth on Wednesday morning after slipping out of the prison kitchen where he was working and strapping himself to the bottom of a food delivery truck.

"We can confirm that police involved in the search for Daniel Khalife are this morning ... focusing their efforts in and around the Chiswick area," the Metropolitan Police said in a statement.

"This activity comes after intelligence-led activity and some confirmed sightings in that area overnight, including calls from members of the public."

The police said Khalife was believed to be wearing a black baseball cap, black T-shirt and dark-coloured bottoms, and carrying a small bag or case.

Khalife was being held in prison ahead of trial on offences relating to terrorism and the Official Secrets Act.

A sign is displayed at Wandsworth prison where Daniel Abed Khalife escaped in London, Britain. Reuters

Opposition lawmakers have demanded answers into how he had been able to escape and why he was not being held at a maximum security prison. There are also questions being asked about the jail's staffing and security procedures.

The hunt to track down Khalife meant enhanced security checks at ports and airports which have led to delays for passengers.

Reuters