'Absolute minima'. Introduced actually after a second incident, the first being the Citation which blocked the M27 at Southampton by touching down on the 02 numbers (it was landing on 20 at the time!)
The second was the '125 at Farnborough on a non public transport flight. Landed successfully off a PAR, and straddled what he thought was the centreline lighting. Unfortunately Farnborough doesn't have centreline lights and he actually straddled the edge lights to the left of the runway touching down on the grass!