DRIVERS are being warned to check underneath their vehicles as thieves in the Bristol area continue to drill into fuel tanks.

Since December 1, at least 20 vans or cars have had tanks drained or siphoned, causing expensive damage, costly losses and, in one case, almost causing an accident.

As fuel prices remain high, police say small transit-type vans are the prime target for the thieves, usually run on diesel.

On December 17-18, then on December 21, diesel was drained from vans belonging to cancer charity CLIC Sargent as they were parked at the offices in Abbey Wood Business Park, Filton.

Jeremy Lune, the head of trading at CLIC Sargent, said: "Every penny we raise is vital to CLIC Sargent's work supporting children and young people with cancer, so we have been saddened by the recent fuel thefts which have taken place. Around £300 worth of fuel has been taken.

"Repairing the fuel tanks on both trading vans, after the first incident, has cost the charity £400.

"One of our vehicles was, again, damaged after the second theft and the fuel tank will need to be replaced.

"The two vans have been locked away and we are helping the police with their enquiries."

The Evening Post has been contacted by the Shell petrol station on York Road, Bedminster, reporting two more incidents involving white vans.

Nick Lloyd, of Symonds Forecourts, said: "In the last four weeks we have had two vehicles come in that have had holes drilled in tanks and diesel stolen. Unfortunately, they then turn up at a forecourt, fill up and, not knowing what has happened, spill all the fuel over our forecourt.

"You can end up with 40 litres of fuel on the floor quite quickly, which is obviously a serious hazard. Every time this happens, the fire brigade have to be called as a precaution.

"We are prepared for this sort of thing – we have special chemicals we put down – but the forecourt has to be closed for at least two hours every time there is a spillage like this.

"It's a safety hazard and it costs time and money for everyone involved."

In Bristol, since December 1, six vehicles have had fuel stolen through drilling and six through siphoning.

And in the middle of December, there were eight fuel thefts reported to police in South Gloucestershire in just eight days.

When one vehicle was targeted, before the driver realised what was wrong, he swerved across a road in Filton as leaking fuel got on to his tyres.

But since an arrest was made on December 23, there have been no more incidents reported in South Gloucestershire.

In 2010/11, fuel was stolen from domestic and business vehicles' fuel tanks 491 times across the force area and 412 times from fuel stations and other business. A general-sized lorry fuel tank costs about £1,000 to be replaced.

Police are advising business owners to use CCTV if they can, secure depot yards overnight and ensure vehicles are locked away out of sight wherever possible.

PC Michael Wedlock, of the priority crime team in South Bristol, said: "We are requesting that members of the public be extra vigilant, particularly in relation to anyone acting suspiciously in relation to vehicles on residential streets or at petrol filling stations.

"Members of the public are advised not to challenge these individuals, but instead to immediately contact Avon and Somerset police by calling 101 or Crimestoppers on 0800 555111.

"In addition, people are advised to park their vehicles in garages or off road if possible. If not, park in a well lit area, make use of alarm systems and do not leave anything valuable inside."