A stretch of Kent motorway remains closed amid the search for an escaped prisoner held on terrorism charges with 150 police officers and staff involved in the manhunt.

Police have shut the M20 coastbound between Junction 8 for Leeds Castle and Junction 9 for Ashford as they hunt for former soldier Daniel Abed Khalife, 21, who broke out of Wandsworth prison in south-west London on Wednesday morning by clinging onto a delivery van.

In a statement, bosses at National Highways said: “At this stage, Kent Police is unable to advise any times for the reopening of the M20”.

At midday yesterday the M20 was closed at Junction 8 and queues stretched back for about three miles approaching the closure, with an estimated delay of about an hour.

The stretch of motorway has been shut as enhanced security checks are taking place at the Port of Dover, in case Khalife tries to leave the country via the Eastern Docks.

Operation Brock Zero has been enforced, with the M20 shut between Junctions 8 and 9 to allow for EU-bound lorries to be parked up along this stretch.

Traffic is being diverted via the A20.

Andrew Rintoul, National Highways south east regional operations manager, said: "I would urge anyone travelling in the area to allow extra time to complete their journey.

"Along with our partners in the Kent Resilience Forum we have carefully planned contingency plans to help keep Kent moving when we do encounter delays at the ports.

"We understand the inconvenience this can cause and appreciate the patience of road users. The situation will continue to be closely monitored over the remainder of today and we will keep you updated on any changes or the removal of the closure."

A search led by the Metropolitan Police has been ongoing but so far there have been no confirmed sightings of the prisoner.

He was declared missing at 7.50am and by 8.37am, officers had tracked down the delivery van Khalife utilised, searched it and spoke with its driver.

Commander Dominic Murphy, who leads the investigation, said: “Over 150 officers and staff have been working around the clock on apprehending Khalife.

"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.

“I recognise and am fully aware of the impact these measures are having on the public.

“We are working to ensure as minimal disruption as possible.

“It is crucial for the public to help us with this search and to call us immediately if they have any information on the whereabouts of Khalife.”

While he is not assessed to pose a threat to the wider public we advise anyone who seems him not to approach him and instead call 999 immediately.

Due to the closure of the stretch of motorway all EU-bound freight must use the M20 while all other traffic must follow the signed diversions, with drivers currently being directed to the A20.

Temporary chief superintendent Simon Alland said: "The closure of the M20 is an emergency measure that is only used following consultation with our partners in the Kent Resilience Forum (KRF) and after a thorough assessment of issues including public safety and traffic volumes.

"The KRF will continue to monitor the situation closely in order to restore the motorway to its full capacity as soon as possible."

Drivers may see stretches of the motorway clear from time to time as groups of freight are moved down the queue in stages when space becomes available.

Non-freight traffic currently being diverted onto the A20 is able to rejoin the M20 in front of the queue at Junction 9.

It comes as extra checks have begun at the Port of Dover, which has released a statement warning delays are to be expected.

“Due to a police matter, there are currently enhanced checks on outbound traffic at the Port of Dover and other portals within the UK,” said the message.

“Please be advised this is currently resulting in some delays at the port.

“However, our standard travel guidance remains unchanged and we will keep passengers updated if they can expect any alteration to their journey.”

Khalife is accused of planting a fake bomb and gathering information that might be useful to terrorists or enemies of the UK, but denies all charges.

He went missing in his cook’s uniform from HMP Wandsworth, which is a category B prison - the second highest level of security.

The prisoner was on remand awaiting a November 13 trial at Woolwich Crown Court in relation to terrorism and Official Secrets Act offences.

His disappearance has prompted questions over staffing levels at HMP Wandsworth and why he was being held in a Category B prison.

The Justice Secretary confirmed an independent investigation will take place following Khalife’s escape.

Alex Chalk told MPs two urgent reviews would also take place regarding the categorisation and placement of all HMP Wandsworth prisoners and all those in custody charged with terrorism offences.

Wandsworth prison’s performance was rated a “serious concern” and watchdogs had issued a string of warnings about the jail in the past year before Khalife escaped.

Chief Inspector of Prisons Charlie Taylor told the PA news agency staff shortages are “the source of many problems” at the prison and later said that “in an ideal world” Wandsworth would be shut.

The Metropolitan Police’s counter-terrorism commander said it is “testament to the ingenuity” of the 21-year-old that there have been no confirmed sightings since he escaped prison.

Dominic Murphy said he was keeping an “open mind” as to whether Khalife had received support from somebody to escape prison and whether he had managed to leave the country.

He said more than 150 investigators and police staff from counter terrorism command working in London on investigation and officers had received more than 50 calls from the public which had provided “some really valuable lines of inquiry”.

In a press briefing yesterday Mr Murphy said: “This was a really busy area of London and we’ve had no confirmed sightings in any of that information, which is a little unusual, and perhaps testament to Daniel Khalife’s ingenuity in his escape and some of his movements after his escape.

“He was a trained soldier – so ultimately he has skills that perhaps some sections of the public don’t have.”

One former inmate at HMP Wandsworth, who worked alongside Khalife in the prison’s kitchens, said the escapee had struck him as “odd” and had told him he was “going to be famous”.

Chris Jones, 53, told BBC London: “He did seem like an odd sausage. One lunchtime he came in saying that he was going be famous. I told him: ‘I think you’ve got on the wrong bus, mate’.”

Mr Jones, who the BBC reported was released in June after being acquitted after seven months on remand, said he was “surprised but not surprised” by Khalife’s escape.

He added: “We always used to joke about that lorry; jump in it and drive off, but there was a lot of security staff around the kitchens so it is a surprise he got through there.”

Khalife was last seen wearing a white t-shirt, red and white chequered trousers and brown steel toe cap boots.

Met Police have issued an urgent appeal to the public to help trace the 21-year-old, who is described as being around 6ft 2ins tall, of slim build, with short brown hair.

Having links to Kingston, officers believe he likely remains in the London area, but may have travelled further afield by now and an all ports alert has been issued across the country sparking delays at UK airports and other ports including Dover and the Channel Tunnel in Folkestone.

Police also confirmed an alert was issued by the Counter Terrorism Command on Wednesday in relation to Khalife through established operational briefing channels to relevant UK police and law enforcements agencies, including those at UK ports and borders.

Restrictions have only just been lifted from the M20 between Junctions 8 and 9 following months of disruption.I

Officers have traced the route of the van after it left Wandsworth Prison and are appealing to anyone who might have seen the vehicle on this route to get in touch.

The van left HMP Wandsworth at 07:32 taking a right turn out of gates onto Heathfield Road. It then turned left onto Magdalen Road. The van then turned left onto Trinity Road (A214) up to the Wandsworth Roundabout. It took the first exit onto Swandon Way (A217).

It then turned left onto Old York Road (past Wandsworth Town station) then left onto Fairfield Street, right onto Wandsworth High Street (A3) staying straight ahead onto West Hill and then on to Upper Richmond Road (A205).

If seen, the public are advised not to approach Khalife and to call 999 immediately, quoting reference CAD 1631/06SEP23.