For once, the crowd outside the Brixton Academy will mirror the crowd inside.
The clusters of middle-aged parents usually spotted waiting on the pavement to collect their teenage kids will be mingling with them on the dance floor to celebrate the 30th anniversary of Rock Against Racism’s greatest triumph.
Music now – as then – is a major political inspiration for young people and Wednesday’s gig reflects changing tastes while sending out the same message. Only this time it’s the British National Party in the firing line, not the National Front.
As in 1978, a diverse group of artists has been assembled to showcase music’s multiculturalism and, as in 1978, Tom Robinson is on the bill.
“The Carnival Against The Nazis on April 30, 1978 was a day that exceeded my wildest expectations,” recalls Robinson.
“We had hoped perhaps as many as 20,000 people might march from Trafalgar Square, so we were gobsmacked when 80,000 turned up for what was a memorable afternoon of music and multiracial solidarity.”
Bands appearing alongside Robinson on Wednesday are Misty In Roots, The Levellers, Alabama 3 and The Thirst, with speakers including Tony Benn.
“I’m going because I remember fascists before the war and I know when there are economic problems it’s easy to find a scapegoat and build hatred against them,” says Benn, who feels the BNP carries a real threat.
“Any political party that identifies a racial group and tries to build power by frightening people against that group is potentially dangerous.”
His views are echoed by Robinson, who adds: “As Thomas Jefferson said: ‘The price of freedom is eternal vigilance.’ Racism is certainly much less overt nowadays but it never went away.
“The struggle for a more just and civilised society is an ongoing fight that each generation has to carry forward.”
The event has been organised by campaigner Geoff Martin, who was inspired by the gig 30 years ago.
“The far right are closer to getting political representation in London than they were when we marched to Victoria Park in 1978,” he says.
“That’s why we need to encourage those who have become cynical and complacent to get off their arses and get back on the streets.”