It is five o'clock in the morning and in a scene that would not look out of place in a zombie film, bleary-eyed youngsters, with fixed stares and many still clad in their night clothes, stagger into a leisure centre in west London.

BBC: Decision time for British swimmer Achieng Ajulu-Bushell

The clock will feature a selection of moving figures representing traditional farmers which will form a rotating Alpine scene beneath 27 bells.

BBC: Clock design