An investigation has been launched after drivers complained they had been sold contaminated fuel.

The Trading Standards inquiry comes after many drivers from across south-east England said they believed they had been sold petrol containing ethanol, which has damaged their cars.

Their vehicles have been juddering, misfiring and had a loss of power.

The investigation follows a complaint, featured earlier this month in the Watford Observer, of a Chorleywood woman who was adamant she filled her car with diesel - but when it broke down her mechanic told her it had been filled with petrol.

Deborah Pattison, of Blacketts Wood Drive, filled her car up at Tesco, Watford.

She said: "I have had a diesel car for five years and always fill up my car at Tesco. I paid for the diesel and picked up my children from my mother's house in Garston.

"As we drove along the slip road to get onto the M25 there was an awful banging and rattling noise and black smoke started to billow out of the car.

"We were all very scared. I pulled over and we climbed up the bank to safety."

Mrs Pattison called her husband, Allan, who drove to fetch her and the RAC collected the car.

The car was taken to Glyn Hopkin in Lower High Street which later told the Pattisons that the car had "fuel contamination" and the tank was full of petrol.

Mrs Pattison said: "I know that I used the diesel pump and I have a receipt to prove it. But it looks like there must have been petrol coming from the diesel pump. I contacted Tesco and showed them my receipt but they have just denied everything."

The Pattisons had to pay £500 to have the tank flushed and have been warned that up to £5,000 of damage may have been caused.

They had to cancel their trip to visit relatives and their children Amba, nine, and Zac, six, have had to spend their half-term holiday at home.

A Tesco spokesman said the store denied that petrol could have come from the diesel pump. He said: "This could not have happened at Tesco. We have not had any other reports and if that had been the case half the cars in Watford would have broken down on Friday night."

However the store refused to release CCTV footage captured on the day to resolve issue.

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