Alan Johnson’s first volume of memoirs, This Boy, is still in the bestsellers’ list, but the Stakhanovite postman has made a second delivery, timed impeccably for the party conference season. It charts his escape from the urban jungle of Notting Hill to Britwell council estate in Slough, via a succession of GPO sorting offices and eventually to high office in the Union of Communications Workers.

Like its predecessor, Please, Mister Postman takes its title from a Beatles classic. The boy left in the care of his 16-year-old sister after their mother’s death dreamed of becoming a rock star. He played in a succession of pop groups and even recorded a demo disc, until the theft of the band’s equipment, including his precious Hofner Verithin guitar, from a room above an Islington pub, put paid to his musical career.

His mother had wanted him to become a draughtsman, because they went to work in a suit, but fellow guitarist Sham, ‘a tall, genial black guy’ persuaded Johnson to become a postman. At least the job had a natty uniform. He married sweetheart Judy, who already had a baby daughter, and when the house they shared in west London with her ‘Nan’ was condemned, the young couple were offered a council house in Slough.

It was boarded up, the garden was overgrown and the estate had a bad name with the police, but it had its own front door and a bathroom. Brought up in a slum, the still-teenage paterfamilias grasped at the lifeline, and they lived there for 19 years. As tenants. Johnson refused to take advantage of Margaret Thatcher’s ‘right to buy’ revolution, even when it became Labour Party policy.

‘Life there was good,’ he reflects. Unlike the raucous streets of his childhood, there was no noise on Saturday nights except the sound of television programmes filtering through the open windows of houses about. ‘We listened,’ he remembers ‘like two anthropologists, to the comforting sounds of domesticity.’

This boy can write. Indeed, he always wanted to, even spending £5 to have a poem published in a vanity anthology. He read omnivorously, using the GPO’s generously timed shifts for intellectual relaxation on his rural rounds in Buckinghamshire. The memories stayed :

One summer afternoon comes to mind. I remember sitting in the van with both front windows wound down to let the breeze blow through, reading Tess of the D’Urbervilles. Time seemed to be suspended on the thick, balmy air. I’d just begun to contemplate standing for the executive council of the union and was glimpsing a life beyond the sorting office. But exciting as this potential expansion of my horizons was, the realisation that if I took this route I might never again enjoy the serenity of Dorneywood Road on a quiet summer’s afternoon gave me a pang of regret. It was one of those idyllic moments which you feel you are already experiencing as a memory, even as it occurs.

Beat that. Johnson did quit his old comrades, and, guided by the union’s avuncular leader Tom Jackson, was elected executive councillor and then national officer. His account of life in the GPO – the Spaniards had nothing to teach them about working practices — is illuminating and entertaining, his trade union history rather less so.

His political epiphany came early. He read Marx and was ‘an opinionated fellow-traveller’ of Tony Benn. Swiftly disenchanted with the extreme Left and its mirthless cynicism he still thought of himself as ‘a rebel’, but settled for being a ‘militant moderate’ loyal to the party leadership. This stance marked him out as a likely disciple of his fellow-guitarist, Tony Blair. Irritatingly, the book stops there, with his painful split from Judy, on the cusp of great things.

Johnson came to workaday Keighley, west Yorkshire, for a Labour fundraising event recently. Easily his party’s most attractive ambassador, he filled the town’s biggest hall at £5 a head. I asked him if there would be a third volume, in which he becomes leader of the band. ‘I couldn’t even make Deputy Leader!” he quipped.

There’s nothing second-rate about his writing. He is a natural.