An embarrassing security lapse at the heart of the Calais crisis has been exposed after dozens of migrants unlocked a supposedly secure door into the Eurotunnel complex.
Despite millions of pounds of British taxpayers' money being spent on reinforced fencing, photographs taken by The Telegraph reveal how a group of 30 migrants breached security and simply walked inside the secure zone.
The men walked up to a gate about a mile from the Coquelles Channel Tunnel terminal near Calais and, within seconds, were inside.
They are believed to have guessed the security code by examining which numbers were dirtiest or most worn on the keypad.
A close examination of the keypad showed the numbers two, four and zero were clearly more worn than the other digits.
Bruno Noel, of the Alliance police union in the Calais area, said the break-in was "strange and very troubling".
"This fence has been there for a long time and as you know when you tap in a code you don't touch all the keys to hide your tracks, so it's quite possible that the keys corresponding to the code are dirtier than the others," said Mr Noel.
"I can't see how else it might have happened.
"Eurotunnel regularly checks the state of the fences and gates and the codes for these."
It comes after a 40-year-old Sudanese man, Abdul Rahman Haroun, was able to evade security and walk 31 miles through the Channel Tunnel from Calais to Britain on Tuesday.
The new pictures emerged on the day the Home Office announced the completion of the first phase of a £7 million to upgrade fencing at the Coquelles site.
The location of the gate is about three miles as the crow flies from the mouth of the Channel Tunnel, although the distance is longer if the curved route of the train tracks is followed. Security at the gate has since been improved since the incident on Thursday evening, and it is now secured with a padlock.
But the incident raises new questions about the programme to enhance fencing around the Eurotunnel site if such obvious weak points still exist to be exploited by migrants.
Most of the 30 migrants are believed to have been intercepted by security staff shortly after the photographs were taken but it is unknown how long other would-be illegal immigrants have been gaining access to the site by similar means.
Britain has committed £19 million extra in funding for fences, CCTV and other security measures at Calais since the crisis erupted in June.
A Home Office spokesman said: "We continue to work closely with the French government and Eurotunnel to tackle the immediate pressures and longer term issues involved in the situation in northern France.
"The UK government has recently invested £7 million for fencing at Coquelles to secure the Eurotunnel platforms, as well as further perimeter fencing.
"The first phase of fencing at Coquelles was completed today.
"Extra Border Force search and dog teams have also been drafted in to further protect the Eurotunnel site.
"Since last year, the UK Government has provided funding to bolster the security and infrastructure of ports in northern France including a £2 million upgrade of detection technology, a £1 million extension of dog searching capacity and an additional £12 million to reinforce security at the juxtaposed border."
Meanwhile, in the Sudanese quarter of Calais' sprawling migrant camp known as "The Jungle" the feat of fellow countryman Abdul Rahman Haroun, who walked to England under the Channel on Tuesday, was praised by his fellow migrants. "He went all the way? That is crazy," said Gido, 19, from Darfur.
"I would like to try, but it sounds too dangerous. But why not if can work? "We have no idea what's down there in the dark, and how would you escape the trains going past?" "Congratulations," said Moussa Daoud, 28, also from Darfur, who has been here eight months and last tried to get to England two weeks ago.
"We can try too."
Another Sudanese man called Moussa, who had been in the camp six months, said he would not be emulating Haroun's 11-hour crossing, which involved coming within inches of trains travelling at more than 100mph.
"I'm giving up the struggle and am claiming asylum in France," he said.
A former fireman who worked in the Channel Tunnel said Haroun's exploit was hard to believe.
"The gap between the train and the side is very narrow - only around 80cm, and given the speed of trains, it would be very easy to get blown off balance," he said. "He would not have been able to get into the service tunnel as this can only be access via armoured doors and you need to ask permission to open them.
"He must have been lucky that the trains were travelling slowly due to diversions inside the tunnels."