Thieves have struck again taking £20,000 worth of bronze and stainless steel valves from a firm in Mitcheldean.

They cut through razor-wire topped palisade fencing and chopped padlocks to steal the valves from Mechtech Valve Services in The Stenders over the weekend.

The business had invested £30,000 in fencing after suffering half-a-dozen thefts in 2005 and 2006 – all occurring just weeks apart – when tens of thousands of pounds of industrial valves were taken.

On one occasion the thieves were so determined that they smashed their way through a breeze block wall to get to the valves.

Ian Wilce, joint owner of the business, said: "The valves were worth £20,000 to us but from a sales perspective they would be worth probably twice that.

"There were so many thefts a few years ago that we actually considered jacking in the business but we're going to keep going.

"We thought the razor wire and fence would keep people out but we're going to have to up our security here even further.

"All the valuable valves are going to be removed from here now and stored at another secure location.

"This will be an extra cost to us but considering how much there is to lose it will have to be done."

He added: "The thieves must have been here for a while so hopefully someone who was passing saw something."

The theft happened some time between 1pm on Friday and 7am on Monday.

It is believed that a transit style van was used by the thieves and would have been parked in a layby on The Stenders during the incident.

Police are eager for anyone who witnessed suspicious activity in the area to come forward.

Anyone with information should call 0845 090 1234, or Crimestoppers anonymously on 0800 555 111, quoting incident 72 of April 18.