At least three of the six contractors shortlisted to build the £40m Olympic velopark have pulled out of the bidding contest.

Shepherd Construction, Wates, and Alfred McAlpine have all ruled themselves out of contention. McAlpine pulled out before its takeover by Carillion.

Of the six contractors announced in September, this leaves FCC Construction, ISG InteriorExterior and Carillion as bidders for the combined velodrome and BMX park. It is also understood that a fourth bidder may have withdrawn.

Most firms said they were not bidding because of a lack of resources. A Wates spokesperson said: “We are disappointed not to be in the position to bid for this, owing to customer commitments. Sports and leisure facilities aren’t core to our long-term strategy.”

Sports and leisure facilities aren’t core to our long-term

Wates spokesperson

One company cited the design’s complexity as a factor, saying: “The roof is an innovative piece of engineering, but we could see we’d be drawn into interminable conversations about costing it.”

An Olympic Development Authority spokesperson said: “We don’t give a running commentary during our confidential procurement process.”