"SEND US MORE ARMS! From every war front comes this call to British workers. Night and day our factory front replies..."

Factory workers assemble the three main components of a tank gun: the barrel, the breech ring and the breech block. When the day shift is over, the equipment is overhauled in preparation for the night shift.

Workers comment on doing the night shift, and how it initially feels strange - but it intensifies the feeling that they're pulling their weight. The mostly female workforce clocks in and gossips while preparing themselves. Nearly two thousand women work in the factory, travelling up to fifteen miles.

A work taker supervises the workers to make sure they have enough to do. A new girl is introduced and shown round the equipment. After the first hour, things are up to speed. Each machine has four operators, two on nights, two on days - earnings are pooled and shared out between them.

At one a.m. the bell rings to announce an hour-long meal break, eaten on long trestle tables in the canteen. A woman livens things up by playing an upbeat piano number, and her colleagues sing along, dance or conduct liaisons with their male colleagues, and the singing continues throughout the subsequent washing-up.

Suitably refreshed and stimulated, the workers return to the factory floor. Blondie, a particularly productive worker, looks set to break her own record.

At four o'clock, when fatigue is starting to set in, there's a tea break, with urns and buns supplied by mobile dispensing teams on the factory floor. One of the women has adopted a pet cat.

Towards the end of the shift, finished parts, chalkmarked 'OK', are partially assembled to let the workers see what they've created. Their job cards go back to the office - one record of their night's work, the other being the tank parts themselves.

At the end of the ten-hour shift, the workers clock out and leave, tired but proud of the work that they've done. Their final job is to ready the factory for the day shift.