MIKE and Kate Westbrook last played east London 40 years ago when, as members of the Westbrook Brass Band and part of a quasi-Salvation Army unit, they performed at Stepney’s E1 Festival.

This time round, along with brilliant saxophonist Chris Biscoe, they welcome in Spring in the basement of the English Martyrs Church in Whitechapel, now the astonishing Vout-O-Renee’s club.

They’re running through A Foggy Day in London Town as I arrive, with Mike’s founding piano notes and Biscoe’s winnowing soprano horn to the fore.

The trio (pictured) begin their set with the ballads You Leave Me Breathless and The Moon’s Our Home, with the drama of the lyrics, starkly and lucidly delivered by Kate, reinforced by Biscoe’s plummeting cadences.

In the Westbrooks’ own song Freedom’s Crown, Kate declares that “the song that freedom sings is for fairness and peace,” yet there’s a stark contrast later in her rendition of Bertholt Brecht and Kurt Weill songs from Happy End, with the compelling, bitter sadness of Sailors’ Tango and Surabaya Johnny: “You have no heart, Johnny,” she cries “and I still love you so.”

Such emotional connection is typical of the trio’s sheer artistry in setting the imagination free.

Strata East was the co-operative jazz label founded by trumpeter Charles Tolliver and pianist Stanley Cowell in 1970 as a reaction to the way that corporate record companies were exploiting and failing to give opportunities to independent and adventurous black musicians.

Within a decade they had produced over 50 powerful albums of audacious post-bop jazz, often with an Africanist theme enhanced by the revolutionary excitation of singers like Gil Scott-Heron.

At the Barbican the now-veteran giants were back to celebrate their achievement and survival. As soon as Tolliver blew his searing horn in the opening number Ruthie’s Song, dedicated to his mother, it was clear that some furious and rare sounds were afoot.

Youthful septuagenarian Alvin Queen drums up a storm and Cowell, reliving the visits the great Art Tatum made to his father’s house in Ohio when he was a boy, struck the keys as if he were communing with Tatum’s ghost.

The wailing Texan tenor sax of Billy Harper blasts out blues-baked notes throughout Effie and the pathfinding bassist Cecil McBee relives the title tune from his 1974 Strata East album Mutima with a plunging vibrato.

Harper portrays the struggling slum cities of Africa and the ghettoes of his own nation as his indignant horn howls through Cry of Hunger and there’s a seething rendition of On the Nile by the quintet.

Throughout, the band attack their tunes with immediacy and fervour as they relive a rebellious era.

As the gig demonstrates, these five powerful artists who have never stopped making freedom sounds and radically rephrasing stories of liberation during a lifetime of insurgent music.