Spare Time gave Jennings the opportunity to explore his fascination with the poetry of popular expression, and a chance to consider through the subject matter of the film, the impact of industrial life on the popular imagination. It illustrates how industrialised people use tradition and their creativity to express the emotional and spiritual side of themselves, in that precious period of relative freedom, the social time between paid work and sleep. He provides a different vision of industrial working class life from that usually offered by the Griersonian style of documentary which raised criticism from Grierson’s supporters.
Although Jennings had considerable latitude on location, previous research and planning had identified three traditional working class activities; brass band music, choir practice and a ‘kazoo band’ in Lancashire. These provide the musical background for each regional sequence, which depicts a variety of other activities associated with working class respectability, such as gardening, the keeping of greyhounds, the division of labour in the home, pub games, football and amateur theatrics. Simultaneously, the film acknowledges the influence of American popular culture upon the lives of the younger generation, with references to cowboy comics, dance bands, basketball and the Victoria Carnival jazz band. In doing so, Jennings presents a working class culture that is protean, rich and diverse, capable of maintaining traditional activities, while accommodating the modern, symbolised by consumerism, American entertainment and culture.
The association of British workers with the American people is achieved by locating work and leisure within the specific historical context of industrial manufacture and peaceful international trade. This is achieved in the introduction of the film, by images of the industrial revolution, such as terraced housing, factory chimneys […]. After these images, the film divides into three distinct sections, introduced and concluded by very brief and highly functional preambles and codas. The commentary, spoken by Laurie Lee, provides the rationale of the film: “This is a film about the way people spend their time. People in three British industries. Steel, cotton and coal. Between work and sleep there comes a time we call our own. What do we do with it?”. Each section begins with a succinct comment about the rhythm of social time imposed on the industries.

Philip C. Logan, Humphrey Jennings and British Documentary Film Movement: A Re-assessment, Ashgate, London 2011