An investigation into four serious accidents on the M25 near Enfield concluded that they were not a result of substantial roadworks in the area.

The study, carried out by the Highways Agency, determined that the speed limit of the road was appropriate and that the roadworks didn’t cause the incidents.

Four accidents took place in five days last year, causing Enfield North MP Nick de Bois to demand Secretary of State for Transport Patrick McLoughlin take action.

The first incident, on Tuesday, October 29, took place on the clockwise slip road of junction 25 at Enfield where a HGV lorry hit a metal barrier separating roadworks from the motorway.

The truck overturned and caught fire, resulting in the death of the driver.

Two days later, another lorry crashed between junction 24 and 25 on the anti-clockwise carriageway in the early hours of the morning. No-one was injured.

On Friday, November 1, a lorry crashed through the central reservation from the same carriageway, resulting in four road workers being injured. One remains in a critical condition.

The whole junction was closed in both directions for several hours, with the motorway opening 12 hours after the incident.

A 48-year-old man was later arrested on suspicion of causing serious injury by dangerous driving.

The fourth incident occurred on Saturday, November 2. No injuries were reported.

The final two incidents, along with the first, were said by the report, to have involved the barrier between the roadworks and the motorway.

In a letter to Mr de Bois, Mr McLoughlin said: “In the context of other similar roadworks sites and current approaches to roadworks management, the road layout is compliant with standards, speed compliance is good and the overall number of incidents is comparatively low.”

Mr de Bois admitted he was “disappointed” with the findings and urged for a speedy resolution.

He said: “I am disappointed that the report leaves more questions than answers. It is, in effect, an interim response to the four accidents we highlighted and it's clear more investigations are being undertaken. These need to be concluded quickly.

“I have little doubt from talking with hauliers and constituents that the road traffic management system needs changes to improve traffic flow and safety but the report has only identified other areas along the route of the roadworks needing urgent changes but not those where the accidents happened.

"I hope the final report will be published soon to ensure every effort is taken to ensure safety and minimise disruptions”

In the final part of his letter, Mr McLoughlin said: “I have also asked the agency to undertake a longer term analysis of the wider principles applied to temporary road works.”