Farrel is definitely puffed after the climb but he cries again, 'The Force of the Nile!'

Every one laughs.

Tara says, 'Mrs Mark, how do we marx this on the map?'

Ian splutters. Every one else bursts into laughter.

Tara goes red. 'Sorry. You know what I mean,' she says.

Penny Marx puts her fingers to her lips and looks meaningfully around her. Scott freeze-frames in the act of throwing a snowball at his dad who is bringing up the rear. Dudley can't stop grinning, but he listens.