Npower 'ewe' by Beattie McGuinness Bungay

In the latest 30-second ad, by Beattie McGuinness Bungay, the famous pair suffer another calamitous mishap when Wallace concocts a scheme to fill his loft with sheep for better insulation.

As poor Gromit shuts the loft hatch, the ceiling begins to crack and the entire flock, along with plaster and rubble, comes tumbling down.

Luckily, Npower Bob appears to tell them there is an easier way to save money – and sheep.