Basically, the F-35B STOVL appears to be a bit light in bring back weight, so the Royal Navy is looking at landing at slow speed,shipboard rolling vertical landing (SRVL).

The aircraft would land at an air speed of somewhere around 60 kt airspeed (the ship would be doing 25 kts, so the deck speed would be 35 kts) to allow for an additional ton or so of fuel or ordinance brought back at landing.