The posts, standing up to two metres tall, were purloined in the dead night from the 1,200-hectare (3,000-acre) wood.

Now in a move to make them harder to “fence” and sell on, the replacements have all been painted blue.

Chris Bray, Recreation Manager, said: “We are at our wits end. The posts are being installed as part of a £300,000 investment in bike routes to make sure riders keep on the right track. We’ve even put posts in concrete foundations, but chainsaws have been used to cart them off. We’re urging everyone to keep their eyes peeled and if they come across blue timbers then drop us or the police a line.”

Rangers are baffled as to why the robbers are stealing the posts. But each one stolen costs money to replace and ties up manpower which otherwise would be getting the routes ready for a grand opening next month.

The colourful new posts are being erected along the three mile “blue trail”, which is aimed at novices and families. Other new routes include a 10 mile cross county route, a six mile adventure trail and a skills loop near the visitor centre. A technical skills areas was opened last summer.

Chris Bray added: “Volunteer trailbuilders, funding partners and rangers have sweated to make this project a success and create a world class centre of biking excellence. The last thing we need is for crooks to slow progress.”

If anyone has any information on the whereabouts of the stolen posts contact the Forestry Commission on 01623 822447, or email chris.bray@forestry.gsi.gov.uk

Subscribe to MBR today and get this Motorex Cleaning Kit and top-selling Cyclepro Tool worth £34.98 FREE. Plus save 10%