A museum exploring the role of working-class people in the development of democracy in Britain from the early 18th century to the present day has officially reopened in Manchester.

Unveiled by health secretary and MP for Leigh Andy Burnham, the People's History Museum has benefited from an extensive £12.5m redevelopment project. The attraction boasts 1,384sq m (4,541sq ft) of exhibition space and nearly 1,500 artefacts on display, while a purpose-built community gallery allows individuals and groups to stage their own exhibitions.

Visitors also have a behind the scenes opportunity to view the only Textile Conservation Studio in the UK, which is dedicated to the preservation of banners. The museum's archive contains the collections of the Labour and Communist Parties. Designs for the refurbishment scheme were drawn up by architects Austin-Smith:Lord, while Paul Cleworth Project Management, Wates Construction, Curtins Consulting, Buro Happold and exhibition designer Headland Design Associates were involved with the delivery.

Consultants True North, Full Circle Arts, digital agency Reading Room and Simon Fenton Partnership also worked on the project, which was handed £7.18m by the Heritage Lottery Fund (HLF) and £2m from the Northwest Regional Development Agency. Dr Nick Mansfield, director of the People's History Museum, said: "The stories behind the rights we take for granted - time off, the vote, social security, the NHS - deserve to be celebrated."

HLF director of operations Dr Robert Bewley added: "The People's History Museum does exactly what it says on the tin! For more than thirty years it has championed stories charting two centuries-worth of ongoing struggle for democracy and social justice in Britain."