British ex-soldier still at large after escaping prison on a food truck

A former British soldier awaiting trial on terror charges who escaped from a London prison remained at large Thursday, as police stepped up security checks across the United Kingdom amid concerns he may try to flee the country.

Daniel Abed Khalife, 21, appears to have slipped out of the medium-security Wandsworth Prison Wednesday morning by strapping himself to the underside of a food delivery truck.

The escape has prompted extra security checks at major transport hubs, particularly in and around the port of Dover, the main boat crossing from England to France.

Khalife is accused of planting fake bombs at a military base and of violating Britain's Official Secrets Act by gathering information "that could be useful to an enemy." He was discharged from the British army after his arrest earlier this year and had denied the allegations. His trial is set for November.

Independent investigation into escape

British Justice Secretary Alex Chalk told lawmakers that "no stone must be left unturned in getting to the bottom of what happened," and confirmed that there would be an independent investigation into the incident. He also said "urgent" reviews into prison categorization would be carried out amid questions about why Khalife wasn't being held at a maximum-security facility.

Chalk said Khalife, who had been working in a kitchen at the prison, escaped at around 7:30 a.m. local time on Wednesday, when a vehicle that had made a delivery left. Shortly afterward, contingency plans for an unaccounted prisoner were activated and police were informed.

Police subsequently stopped and searched the vehicle.

"Strapping was found underneath the vehicle, which appeared to indicate that Daniel Khalife may have held onto the underside of it in order to escape," Chalk said.

More than 150 investigators and police staff are on the case, according to London Metropolitan Police Commander Dominic Murphy, who is the lead investigator.

"We have issued a nationwide alert that has resulted in increased security at our ports and borders. However, currently, there have not been any confirmed sightings," he said.

Critics flag capacity issues at U.K. prisons

Opposition politicians have sought to pin the blame on the Conservative government, which has been in power since 2010. Many U.K. prisons, including Wandsworth, are over capacity and short of staff.

The escape could hardly have come at a worse time for a government that is already scrambling to get all schools to reopen for the new academic year amid concerns over crumbling concrete.

"It simply beggars belief that a man being held on suspected terror charges was able to escape a prison by clinging to the bottom of a food delivery van," said Shabana Mahmood, the justice spokesperson for the main opposition Labour Party. "How is such an escape even possible?"

Charlie Taylor, who scrutinizes detention facilities in England in his role as the chief inspector of prisons, said staff shortages are "the source of many problems" at Wandsworth. Taylor said it should be standard practice for vehicles entering and leaving the prison to be checked, and that a prisoner has to earn a "certain level of trust" to be allowed to work in a kitchen.

"But the issue that we are particularly concerned about is there are too many prisoners in Wandsworth for the amount of staff who are there," he said. "And that, ultimately, is the source of many of the problems in the jail."

In an annual review, published in July, Wandsworth Prison was deemed to be a "serious concern." The prison, which is in the middle of a residential area, holds around 1,600 defendants appearing at London courts and offenders due to be released in five wings.