Top 10 UK airports by passenger number for 2015:

1) Heathrow  75 Million

2) Gatwick    40 Million

3) Manchester 23 Million

4) Stansted   22 Million

5) Luton      12 Million

6) Edinburgh  11 Million

7) Birmingham 10 Million

8) Glasgow    8.5 Million

9) Bristol    6.5 Million

10) Newcastle  4.5 Million

Passenger numbers from 2015,source: CAA

https://www.caa.co.uk/Data-and-analysis/UK-aviation-market/Airports/Datasets/UK-Airport-data/Airport-data-2015/