Three Britons have been held for seven weeks without charge in Switzerland over "minor driving offences" during an organised motoring holiday.
The men were taking part in the Cannon Run, a European driving tour. They were arrested on 4 June and have been held in custody since without bail.
It is alleged they were racing their cars on a Swiss motorway which could result in a four-year prison term.
James Cannon, tour organiser and friend of the trio, denied the accusation.
Swiss prosecutors said the men were being held over possible violations of Switzerland's road traffic laws.
Julian Wilson, 40, from Nottinghamshire, David Bentley, 49, from Shropshire, and Adrian Harrold, 45, from Wolverhampton, were driving three Nissan GT-Rs during the trip from Maidstone to Monaco when they were arrested near Zurich.
Mr Bentley's daughter was forced to postpone her wedding as he could not be there to walk her down the aisle and he also missed his son's prom. Two of the men have spent their birthdays in prison.
Cannon Run 3000 is described as a "luxury driving holiday for every car fan" taking in Europe's best roads with an emphasis on "safe driving".
Mr Cannon, who had warned people taking part about "extreme" driving laws in Switzerland, said no-one taking part was racing.
He said the men were being held for nothing more than "minor driving offences" including a "small speeding issue", that in the UK would have been a "slap on the wrist".
Prosecutors have suggested to the Swiss media the men were being held for taking part in a street race, an offence punishable by up to four years in prison.
A spokeswoman would only confirm that it was over a violation of Switzerland's road traffic laws.
The BBC has discovered that no charges have been formally brought and the investigation is continuing.
However, the reason the men have remained in prison is because they are currently in what the Swiss call "untersuchungshaft", or investigatory detention.
A Foreign Office spokesman said: "We have been assisting three British people since their detention in Switzerland since 4 June.
"We are providing support to their families and remain in contact with the Swiss authorities."
Analysis: Imogen Foulkes, BBC Geneva correspondent
After the Le Mans Grand Prix disaster in 1955, in which 84 people were killed, Switzerland decided to ban car races completely.
Despite some calls for reintroducing them, they remain banned and it seems unlikely they will ever be permitted again.
But that has not stopped some drivers from staging their own informal, often spontaneous, races on Swiss alpine roads and passes.
It is speculative, but it may be that the Swiss authorities want to use this case as a warning to others. The Cannon Run attracts a lot of attention from car enthusiasts and broadcasts its events on social media.
The reason for the long detention is not clear, but it is possible the three are considered a flight risk, and are therefore being held in detention rather than let out on bail.