MILL chimneys billowing with smoke, suit-wearing men on the terraces of Burnden Park and tots in tin baths in front of the fire.

In 1937, Bolton became the focus of the Mass Observation Worktown project — an investigation into the habits and customs of the people of Britain.

This year, it is 75 years since Humphrey Spender travelled to the town armed with his camera to document Boltonians at work , rest, play, politics and worship — and having their hair problems sorted outdoors.

Bolton Museum will host a special exhibition marking the anniversary of the start of the research project.

Among the many questions the Worktown project sought to answer included how many pints of beer did the average person in Bolton drink a night?

The answer — in the course of a single Thursday night pubgoers drank, on average, 3.16 pints of beer and, on a Saturday, the average went up to 3.45 pints.

Cllr Chris Peacock, Bolton Council ’s cabinet member for culture, said: “The Worktown project is a fascinating collection of photos, diaries and paintings, which captured a specific time in Bolton’s history.

“It recorded in great detail how people worked, ate and lived, even their political and religious beliefs and how they spent their leisure time.

“It is a really important collection both for Bolton and also for social historians across the country. We hope that people will come along, both from the local area and also from across the UK, to see how people used to live and to help us identify some of the people and places featured in the photos.”

Mass Observation was founded by a group of young writers and intellectuals, led by Tom Harrisson.

They believed British society was deeply divided, with very little understanding or consideration given to the lives and opinions of ordinary people.

It has been documented that Mr Spender, who died in 2005 aged 94, found the experience of taking documentary photos particularly stressful and disliked the intrusiveness of his work.

After the Second World War his interests shifted from photography to painting and textile design.

The exhibition will include selections from more than 850 photographs, which offer a fascinating insight into the lives of ordinary people living and working in pre-war Bolton.

They candidly capture people going about their daily lives, visiting local pubs, the theatre, parks and public spaces.

It also features photographs and paintings by artist and poet Julian Trevelyan and filmmaker Humphrey Jennings, as well as observations made by people such as Bolton’s Bill Naughton, who went on to become an award-winning playwright.

Other artefacts in the exhibition include the original suitcase filled with magazine and newspaper cuttings used by Mr Trevelyan to create collages in Bolton streets, as well as Mr Spender’s camera, which was used for the majority of the photographs in the exhibition.

In 2009, the University of Bolton set up the Centre for Worktown Studies to carry out and promote academic research around Mr Spender’s collection.

Dr Bob Snape, head of the centre, said: “This exhibition is a fitting celebration of the 75th anniversary of Mass Observation’s Worktown project.

“There is growing national and international interest in the project and this exhibition should attract many people to Bolton.”

The exhibition, which has been curated by Caroline Edge, a PhD research student at the university, will be organised into themes, including Davenport Street — the street in which the Worktown project was set up — leisure, politics, religion, work, art and holidays.

A special preview evening will be held at the museum on Friday, September 21, for invited guests and attended by the Mayor of Bolton, Cllr Guy Harkin.

To coincide with the exhibition, Bolton Museum is also launching a new website — boltonworktown.co.uk — which will include all the photographs from the collection for the first time.

Images will be linked to maps of Bolton and visitors to the site will be encouraged to help identify places and people.