Doris the chatterbox usherette worked in a munitions factory. Unlikely though it seems, Fred the self-important commissionaire flew Spitfires in the Battle of Britain. But now it’s 1946 and they both work for Odeon Cinemas.

Fred and Doris are actors, hosts of a 90-minute workshop at London’s National Film Theatre, in which Key Stage 2 pupils join a post-war children’s Cinema Club.

The two characters are so convincing that at one point the children start saying “Sshh!” to Doris because they want to see the next piece of film. They clearly don’t realise she is an actor.

Doris and Fred’s banter links the archive footage, and they are full of anecdotes about what they and their families did during the war. Fred’s little cousins, for example, were evacuated to Yorkshire. Doris’s sister Mabel was a land girl. Doris herself still has to paint her legs with Oxo because nylons are so scarce.

The children are especially intrigued by the projectionist, Bernard, at the back of the auditorium. Every time a new film is cued they turn round to check that he’s still there.

The purpose of the package is to give children a light-hearted taste of what life and cinema were like during and just after the war. There’s about 50 minutes of film - Foxhunt, a surreal early British multicoloured cartoon with dancing horses and car-driving foxes; Tom’s Ride, a short black and white moral tale; and an exciting 18-minute episode of the sci-fi series Flash Gordon.

The programme includes documentary shorts. A Pathe newsreel shows young evacuees being sent off to the colonies. Food Flashes exhort the population to eat carrots and potatoes instead of bread. And a 1942 Sensible Buying film tells women to use old curtains to make new dresses.

To prepare for the visit, it’s suggested that teachers help the children get into role by imagining what went on in their lives during the war. Were any of them evacuated? What did their grandparents do during the war? What was it like going to a children’s cinema club on a Saturday morning? How did it feel during an air raid? Did they have an air raid shelter?

A resource pack includes the words of the Odeon Club Promise: “I promise to be thoughtful of old folks and to be kind to animals and always to play the game.” It also gives the words and music of the Odeon Club Song - “Do we ask for favours? NO! Do we help our neighbours? YES!”. During the performance, the words appear on the screen, complete with bouncing ball.

Fred and Doris get small groups up on stage to take part in scenes and games. In one game, they have to guess how much bacon, milk, and eggs an adult was allowed each week. The answer is two rashers, three pints, one egg. This leads to the recipe for MI5 stew, so-called because the ingredients were a closely guarded secret: pig’s trotter and stomach lining boiled with sheep’s brain and root vegetables. The predictable audience reaction is “Ughhhh”.

Twelve children are given name tags, gas masks and suitcases, and board an imaginary train for Yorkshire. On their arrival a billeting officer - Fred - divides them up and sends them to live with various women - all Doris in a selection of hats.

An air raid warning sounds and a slide of a London Underground station packed with people comes up. Doris and Fred reminisce about running for cover and the camaraderie in the shelters. Doris produces the first banana anyone has seen for six years. Fred eats it behind her back and the children shout at him. A good time is had by all.

ContactEducation unit, British Film Institute Tel: 020 7957 8983. Entertaining the Nation runs twice daily for a week in February, June and October. Tickets pound;3 each. The package also travels to venues outside London. For other events for KS2 to KS4, call the education unit.