Passengers on a packed GWR service to Totnes were advised to expect a delay to the catering service after an unexpected passenger was discovered on board.

The Saturday service from Plymouth to London via Totnes was heading east when the guard made a surprise announcement. There was, he said, a rodent on the train.

Catering services had been affected, and the trolley would not be deployed until staff could establish that there was no risk of contamination.

The message produced a predictable level of concern, curiosity and the sort of speculation that can flourish when several hundred people are confined to a railway carriage with nothing better to discuss.

So was it a mouse? Or a rat? Nobody appeared to know.

There was, however, a growing suspicion that the creature might have been making the journey without a ticket.

One passenger wondered whether GWR had inadvertently provided a free first-class journey to Ratatouille, the Parisian rat famed for his culinary ambitions.

There was another twist to the railway’s increasingly unlikely menagerie when a Totnes station staff member recalled that children had released dozens of crabs on another train the previous week. The implication was clear: GWR may need to reconsider its onboard catering policy.

The trolley eventually resumed its duties once the contamination risk had been assessed.

Whether the rodent was apprehended, however, was less clear. Nor was there any word on whether it had been charged for its journey.

For passengers, at least, it provided something more memorable than the usual announcements about connections and buffet availability.

And for one small creature, there was potentially a long way to go before the next stop. Paddington, perhaps, was always its final destination.