In message OYtco.163011$6C1.65588@hurricane, Robin
writes
I've not used London City recently (and am a UK national). The OP
appeared to be posting from the USA and I don't think has given
nationalities. So possibly a bit more than 20 minutes if arriving from
outside the UK and hits a queue for immigration?

Things might have changed since I last used City airport (over a year
ago) but about 99% of users seem to be EU citizens so they don't appear
to bother with separate immigration lines. A few years ago I came back
with a colleague who had US passport but the airline didn't hand out the
landing cards for non-EU citizens as they generally do. It took City
Airport a bit by surprise that anyone would need a landing card, but
they found him one, it took him all of a minute to fill it in, and we
were on our way. Out to the street within 10 minutes of landing, as is
so often the case there. If only all airports were as efficient.

--
Clive Page