Great Western Coffee Shop

I noticed a poster on my travels today advising passengers they should be at their platform 5 minutes before scheduled departure.
Not something I've seen before, is this a new thing for rail travel, as not something I've seen before but noticed the poster at 3 stations today.
If passengers took note it may stop what I've seen to be potentially dangerous running on stairs and footbridges.
And no moaning about doors locking 40 seconds before departure, as you'd be on the platform 4 mins 20 before then anyway!

And when your official connection is less than 5 minutes?

Perhaps they don't display the posters at those stations.

Are there many with a connection time less than that? I must say I'd be reluctant to rely on it when planning a journey.

Quite a few stations are listed in the full National Rail timetable as have minimum connection times of 5 minutes or less.

A journey I've undertaken on a few occasions gives a valid itinerary of arrival at Redhill xx06, departing on next train at xx09.

2 minutes was always minimum connection time unless stated otherwise. A look through the timetables stations with a longer minimum connection have a number in a black box next to them.
Nice contradicting publications as always

Stations on the London to Reading corridor all have 3 minute connections. The lowest we have is at Avonmouth which is 2 minutes.

Regarding the poster, correct me if I'm wrong but I believe that is a Cycling by Train poster where we advise customers with bicycles to be present on the platform at least 5 minutes before the train arrives. This is so platform staff can advise them on where to go.