With the August Bank Holiday coming up this Monday (29 August), business travellers in the UK will see delays, cancellations and changed timetables from Saturday to Monday.
Expect crowded trains, amended timetables, longer journeys and generally a difficult travel experience.
The Heathrow Express and Heathrow Connect trains to Paddington station, as well as Eurostar trains from St Pancras to France, are planning to run regular schedules.
But every other UK train line will be amending their timetable, rerouting trains, running slowly and generally experiencing disruption.
Here's the full official map of disruption, which you can also view in PDF form on the UK National Rail website.
Of course, in London, the Notting Hill Carnival and Rugby League final will also mean that public transport is overloaded.
There will also be part closures to four London Underground (Tube) lines, so check whether the access routes to your hotel will be working.
If you're heading to and from the airport, this might be the trip to ask your hotel concierge's advice for getting around -- even before you arrive.