I expect what would happen would be that the RN would launch a (many) Vertically Launched Tomahawk (or similar Cruise Missile) with the GPS for a specific (various) points along the runway to deny use.
Or a ALCM (Storm Shadow/SCALP) from a Tornado many miles away.
Former seems more realistic.
But the Nimrod has a bomb bay doesn't it; and I seem to remember that there was talk on here about Storm Shadow/SCALP being fitted (rumour network remember) to the MR4