Dissenting voices find new home

Well, how very unfair the criticism was. The first thing to say, when you see the thing in front of you, is that it's not actually a donkey jacket at all. It's a short, dark green overcoat, which Foot said he'd bought at Harrods (a dangerous confession for a socialist). He added that the Queen Mother had complimented him on it. It's one of the more offbeat exhibits at a museum which traces two centuries of working class history and has just reopened after a stylish two-year redevelopment costing 12.5m.

Alongside the coat is one of his walking sticks, which Foot broke in half while emphasising a point at a meeting, and a Spitting Image puppet that makes him look as dishevelled as a scarecrow in a gale. If you must see a real donkey jacket, there's one in Carried Away, a photographic exhibition taking a novel look at protests, demonstrations and sit-ins. The pictures, from Suffragettes to CND, show people "standing up (or sitting down) to be counted" with some "literally getting carried away", generally by the police.

The jacket is covered with badges – Coal Not Dole, Free Nelson Mandela, Victory to the Miners, People's March for Jobs, No Cuts, Smash Apartheid. For good sartorial measure, there's also a duffel coat with more badges – US Bases Out of Britain, Greenham Women are Everywhere, Pay the Health Workers, Jobs Not Bombs.

A whole era of here-we-go protest, of strikes and marches, dissent and struggle, is summed up in those two jackets. In our bland new century, it stokes a glow of nostalgia as warm as any picket-line brazier for a lost age of radicalism. Button the duffel-coat toggles and put up the hood; we're in for a cold night.

But enough of tailoring. The museum, just past a street aptly called Dolefield, rears like a great brown iceberg over the River Irwell. It's a thriving place, with a new Left Bank caf-bar featuring Omelette Arnold Bennett (with smoked haddock) and a collection ranging from the world's oldest trade union banner, through photographs of the Orgreave battles during the Miners' Strike, to Attlee's pipe.

Pipes are handy political props. A caption points out that "politicians from Stanley Baldwin to Harold Wilson smoked pipes to give themselves gravitas." It seemed to work. A Labour poster for the 1966 General Election, in which Wilson was up against Edward Heath and Jo Grimond, showed just a pipe and an ashtray, with a caption echoing a much-mimicked TV advert for Mackeson stout: "By golly he does you good". It was superb "branding" before anyone thought up the term, associating Wilson with down-to-earth pubs, popular TV culture and the probity of pipe-puffing. Who says spin-doctoring is a child of New Labour?

Anyone under, say, 30 may already be puzzled by some of the references in this piece. Greenham? Grimond? Orgreave? Dr Nick Mansfield, the museum's director, acknowledges as much. "Ninety per cent of young people won't know what a trade union is," he says. "So you have to explain things at a basic level."

He's being refreshingly realistic. After talking to him, I watch a group of teenagers struggle to recognise a row of politicians. They can name Margaret Thatcher ("Scary woman!" one whispers) and Tony Blair (his hair teased into devilish horns, their teacher points out). They can just about place John Major. But Kinnock, Wilson and Barbara Castle draw a blank. Across the gallery, a woman is telling her young granddaughter about outside toilets. "Toilets?" asks the girl incredulously. "Outside?"

The museum has addressed all this. "In our captions, I suppose we're trying to write for a 10-year-old, and supplement that with labels that more erudite people will be interested in," says Mansfield. He admits that museum-goers don't read "great slabs" of text any more, which is why the captions are so pithy – "history for people prepared to read 50 words" as they put it.

But there's no dumbing down. Could you have a crisper, more eloquent, summary of the Industrial Revolution than: "It transformed society. As one section of society grew rich, another was condemned to a life of poverty and terrible living conditions. Time became master, as life in the new factories was dominated by the clock."

The museum puts itself in context with the simple display in its foyer. Painted along a row of stern black ballot boxes is a graph charting Britain's ever-increasing political apathy since the Second World War. In 1950, charged with Welfare State enthusiasm, almost 84 per cent of the electorate voted. By 2001, it was down to 59 per cent, with a tiny boost to 61 per cent in 2005.

Public disillusion with politicians, underscored by the expenses scandal, will probably make that seem a huge turnout when we finally vote this year. But remember, as one of those mini-captions says: "Two hundred years ago, Britain's political system was corrupt and controlled by a few rich men. Without the right to vote, ordinary people had no power to change their lives."

Thomas Paine expressed these frustrations in his 1791 tract The Rights of Man – and here, glory be, is the surprisingly small table at which he wrote it, together with a snuff box containing a lock of his hair, a disturbing bit of lefty idolatry if you ask me. His death mask shows that his nose, if not his politics, leaned to the right.

The Chartists are here, the Tolpuddle Martyrs, the Levellers, the Match Girls... it's like a crash course in democracy, a handy glossary for Tony Benn's speeches. Looming colourfully over them all are trade union banners, the heraldry of the working man, with their gleaming gold and their glimpses of a better life.

The museum has 400 of them, the world's largest collection. Here is the banner of the Amalgamated Society of Woodworkers, with its sober-faced men carrying saws and folding rulers; the Operative Society of Bricklayers; the National Amalgamated Hosiery Federation. But the show is stolen by the world's oldest banner, for the Liverpool Tinplate Workers in 1821, a lyrical thing with fair-haired women and stooks of corn, and by the oldest miners' banner, from Ashover in Derbyshire, 1830. A couple of soft-hatted miners lean rather louchely against a shield and a lion roars over them.

Their world looks surprisingly settled, but these were heady days in the campaign for democracy. The museum pays tribute to one of the 19th century's most notorious incidents which happened not far from here – the Peterloo Massacre of 1819. In St Peter's Fields, a 60,000-strong crowd protesting for political reform was charged by sabre-wielding cavalry.

Eleven people were killed and many hundreds wounded. In the corner, press a button and hear extracts from political speeches. How low-key Harold Wilson sounds as he famously tells the 1963 Labour Party Conference about technology's "white heat of revolution": so conversational, so downbeat, that it's amazing his vague vision enthused his audience. And how young and idealistic Tony Blair sounds in his first speech as Prime Minister in 1997: piping hopefully about the "pursuit of noble causes".

The museum houses the Labour Party's own archive collection – "the most complete of any political party in the world" says Nick Mansfield. It also has archives from the Communist Party, and a collection of political cartoons reckoned the best outside London.

It's not a party-political museum, though, and has staged exhibitions about the Liberals and the Tories, with the latter opened by William Hague.

"He was wonderful; he gave the best speech we've ever had," says Mansfield. "The worst speech we've ever had by a politician was also given by a Yorkshire MP. I'm not saying who..."

A Musicians' Union display, incidentally, includes a Fifties jukebox. Among the records you can play is one by the great American soul and R&B star... Wilson Pickett. Neat.

People's History Museum (0161 838 9190; www.phm.org.uk) is at Left

Bank, Spinningfields, Manchester M3 3ER. Open daily 10am-5pm.

Free admission.