Rule 5 provides for this, but repeatedly (Barton, Biggin Hill, Southampton, most recently) does not work because pilots do not comply with it. The Authority doesn't prosecute, though, so that bit of the Rule is derelict and needs attention, either by way of prosecutions to make people comply, or by an acceptance that an aircraft which has suffered a power failure has some sort of 'right' to come to earth on someone's home...
See:
http://www.caa.co.uk/docs/503/Annual...s2010-2011.pdf