By Michael Daventry

LONDON

A Sudanese migrant walked almost the entire length of the high-security rail tunnel connecting France to Britain, in the gravest security breach seen this summer, the Times reported on Friday.

Abdul Rahman Haroun, 40, jogged along the narrow platform next to the tracks in the southern tunnel, taking cover in doorways as trains hurtled past at 160 kilometers per hour.

He was caught by police “less than 1,000 yards” (900 meters) from the tunnel’s British exit, according to the report. He was arrested and sent to immigration detention.

Haroun would have evaded dozens of security cameras and climbed over at least four fences before reaching the French entrance of the 50 kilometer (31 mile) tunnel.

“It was incredibly dangerous and totally illegal and also pointless because it is not possible to walk through without being detected,” a spokesman for Eurotunnel, which operates the Channel tunnel, told the newspaper.

It was the most severe security breach this summer at the tunnel, which has seen thousands of access attempts by migrants from Africa and Asia hoping to start a new life in the U.K. Migrants usually try to stow away in trucks to get across.

Nine people have been killed trying to get into the tunnel since June. Hundreds more migrants are waiting in unofficial camps in the northern French town of Calais for an opportunity to make a crossing.

On Monday Philip Hammond, the British foreign secretary, announced tightened immigration controls around the tunnel. The measures include more funding for fencing and security equipment, as well as up to 100 more guards to patrol the Eurotunnel terminal.

The incursions by migrants and a simultaneous strike by French ferry staff near Calais has caused long delays to travel between France and the U.K.

A queue of lorries on the British side of the tunnel waiting to cross had extended to 58 kilometers (36 miles) -- longer than the tunnel itself -- by last weekend, although their numbers have since begun to fall.