5Luton
5: Luton (+46k since 2012)
Probably more notable for its airport than anything else, Bedfordshire's Luton is ranked fifth overall.
Those who can get away from the planes might go to Whipsnade Zoo, or Wardown Park (pictured).
Most likely, Luton would be used as a hub for travelling into London, which is what the 16k visitors from France and Ireland may have used it for.
Image credit: Supernitram/Thinkstock