CRIMINALS are believed to have been behind Tesco’s contaminated fuel crisis which caused dozens of motorists to break down after filling up with dodgy diesel.

Police have launched a criminal investigation following allegations diesel destined for the Branksome forecourt was stolen and swapped for sub-standard fuel.

The garage was boarded-up for almost two months after scores of motorists broke down having tanked-up at the forecourt on September 18.

A Tesco spokesman said: “The contamination of fuel that occurred at our Branksome filling station last year is now a criminal investigation. We are cooperating fully with the police in their enquiries.”

The investigation is being led by Essex Police, which confirmed one man has been arrested on suspicion of theft.

A force spokesman said: “Police are investigating an allegation of theft following an incident on September 18, 2014, where fuel was allegedly removed from a tanker and replaced with non- road fuel diesel. “The incident is alleged to have happened in Oliver Road, Grays, Essex, at around 3am on September 18.”

The spokesman said a 57-year- old man from Essex was arrested on December 19 and has been bailed pending further enquiries until mid-February.

The busy Branksome garage was closed for more than eight weeks while Tesco investigated the cause of the contamination and the affected underground tanks were replaced.

It’s thought more than 100 motorists broke down after filling up with contaminated fuel, although the supermarket giant has refused to say exactly how many people were affected . Many who contacted the Daily Echo said they were facing repair bills totalling thousands of pounds, as well as enduring the stress and inconvenience of breaking down.

The Tesco spokesman said affected motorists have been reimbursed for the cost of repair works and courtesy cars were provided where appropriate.

He added: “We are grateful for the patience of our customers throughout this time and apologise for the trouble they’ve been caused.”