A £3,000 bright yellow three-tonne cherrypicker was stolen from Oswaldtwistle between 6pm on Monday and 6am on Tuesday.
Owner Anthony Poole was astonished to find it gone from Westend Business Park as he had left it with the jack legs down.
That means it would have been almost impossible to move without the keys.
Mr Poole, 45, has offered a £500 reward for information leading to the recovery of the vehicle, which is 20ft long by 7ft 6in wide.
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