Dropping someone off at UK airports can come with a surprise charge—on average...

https://devinzort649.timeforchangecounselling.com/is-it-cheaper-to-park-or-get-a-taxi-both-ways-for-a-weekend-trip

Dropping someone off at UK airports can come with a surprise charge—on average about £6.51. Heathrow’s fee is around £7, while Gatwick hits closer to £10