This has been discussed here a couple of times
The only airline that has used the Fokker 70 into LCY
was Air Littoral (on behalf of Air France). The Fokker 70s needs some software upgrades to the braking system, so you cannot use a standard Fokker 70. The three ex Air Littoral Fokker 70s are, to the best of my knowledge, the only Fokker 70s ever modified.
Runway length was the main problem for the Air Littoral/Air France Fokker 70 which had, despite the modifications to the brakes, difficulties on a wet LCY
runway. This was the reason why Air France switched from Air Littoral Fokker 70s to Cityjet 146s on their Paris service after approx 18 months.
So, to put it short, while the Fokker 70 can operate from LCY
, it is not an ideal aircraft.