Looking in my travel history, I found that I travelled from Brussels to London in Jan 2015 on a throwaway return (23 pounds cheaper) without going back.
Never heard anything from Eurostar since, so given that the question is about actual practice, no, at least in Jan 2015 they weren’t enforcing any penalties.
Credit:stackoverflow.com‘
4 Mar, 2024
5 Mar, 2024
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