No civil aircraft requires reverse thrust to stop the aircraft. Aircraft certified under FAR 25 (or it's equivalent) do not take credit for reverse thrust in the Landing Performance certification. Reverse thrust is a bonus, as is any AFM data providing you with landing distances using reverse thrust.

Regards,

Old Smokey

I certainly would not try exiting LGW or anywhere else via a R.E.T. (rapid exit turn) at the maximum 60 knots in a 747 or other wide-bodied type. Whilest the use of reverse is not factored into certification, speedbrakes or more correctly, ground-spoilers, are. From the Boeing Flight Crew Training Manual for the 747-400 "unless speedbrakes are raised after touchdown, braking effectiveness may be reduced initially as much as 60%".
As the old adage goes "bang it in, stand on them and slam them into reverse!" then leave the runway quietly and wait for the complaints from the cabin crew!!

I knew I was doing it right:O