We always suggest you buy before you travel.
It is surprising how many people get off the plane abroad and head straight for the nearest foreign exchange desk.
Many of these now are also located in the baggage reclaim hall. They have a bit of a captive audience.
You arrive at the airport. Do not have change or cash and then you start to think about the taxi to your hotel. Tips for hotel staff. Need to get a bottle of water. All theae things go through your head. You are waiting for your suitcase so head over to change some money.
The rates will rarely be good and you would been much better getting at the UK airport before you left if you had left it until the last minute.
