But police believe they may have been disturbed because they left more than £1,300 behind.

The raiders forced the back door of the William Hill Betting Shop on Harpers Lane with an unknown implement but once inside switched on the lights and re-positioned posters in the window to block the view of passers-by.

They used cutting equipment to cut through the counter and used a power drill to break through three inches of concrete then an angle grinder to get into the safe.

Sgt Sonia Spencer from Chorley Police said: "The premises were secured by the deputy manager at 9.40pm on Friday, December 5, after close of business. The offenders have been there a considerable amount of time but possibly were disturbed. The lights were turned on and posters in the window were repositioned to block the view of passers-by.

"The safe contained £3,228 and they have made off with £1,873.88 in cash undetected. They used an angle grinder to get in the safe and a blade was left at the scene. They also left glove marks and fresh chewing gum so there may be some DNA."

The incident happened sometime between 9.40pm on Friday and 7.45am on Saturday, if anyone saw or heard anything, they are asked to contact Chorley police on 0845 1 25 35 45 or Crimestoppers anonymously on 0800 555 111.

A spokesman for William Hill Bookmakers said it was not company policy to comment on such incidents, however through the Association of British Bookmakers there would be a reward available for information leading to the successful conviction of the person or persons responsible.