For most passengers, minimum check in time is 30 mins. I did ask eurostar staff what absolute minimum they'd accept passengers. Was told 8 minutes. My personal 'best' was 10 minutes. Back in a July 2007 at a busy Saturday morning Waterloo. Mind you, I did have to ask an official at the ticket gates ever so nicely to let get past others in the queue for other train. She was not impressed. Caught my train, though....phew. Most of the time, I turn up 20 mins beforehand. But, if everyone had my leave it to the last minute attitude, it'd be chaos. What experiences have others had at Paris Nord, Bruxelles Midi, London St Pancras ?