Geraint Thomas has appealed for the return of his Tour de France trophy after it was stolen during a cycle show in Birmingham.

The trophy, which was on loan to a bike manufacturer, was taken when it was left unattended last month at the city’s National Exhibition Centre but the theft was revealed to the public only on Thursday.

“It is incredibly unfortunate that this has happened,” Thomas said. “It goes without saying that the trophy is of pretty limited value to whoever took it, but means a lot to me and to the team.

“Hopefully whoever took it will have the good grace to return it. A trophy is important, but clearly what matters most are the amazing memories from this incredible summer – and no one can ever take those away.”

But in a sporting heist that is likely to generate attention on the scale of that accorded to the discovery by Pickles the dog of the stolen Jules Rimet football World Cup trophy more than 50 years ago, the circumstances in which the theft took place were shrouded in mystery.

West Midlands police said in a statement that the force was contacted on 2 October about the theft of the trophy from the NEC sometime between 6.30pm-7.30pm on 29 September.

Team Sky, with whom Thomas rides, said police were investigating the matter. “In the meantime, Team Sky are liaising with all relevant parties to agree on the best course of action to resolve the issue,” it added.

The team said it had been displaying its three Grand Tour trophies around the UK and that they had been loaned to the cycling company Pinarello for the recent Cycle Show at the NEC in Birmingham.

“Regrettably, during the clear-up operation at the end of the event, Geraint Thomas’s Tour de France trophy was momentarily left unattended and stolen,” it said.

Richard Hemington, the managing director of Pinarello UK, said: “We are obviously devastated about this. We accept full responsibility and have personally apologised to Geraint. Obviously we all hope that the trophy can be recovered.”

News of the crime was greeted with shock by cycling fans, including some who took the opportunity to land a jibe at Chris Froome, who was usurped in France by the victorious Thomas as Team Sky’s de facto leader.

“Police release image of man wanted in connection of theft of Geraint Thomas Tour de France trophy,” said one Twitter user, attaching a grainy black and white photo of Froome.

Froome reacted on social media to news of the trophy’s theft, tweeting the word “appalling” and attaching a sad face emoji.

Thomas won the team’s sixth Tour de France title in seven years in July. It was the fourth successive Grand Tour win for the team after Chris Froome won the Tour and the Vuelta a España last year before clinching this year’s Giro d’Italia.