The sense of loss tumbled out in anecdotes exchanged after Wednesday’s funeral of Bob Kerslake, the former head of the civil service and one of the greatest public servants of our era. The words recurred: integrity, decency, a force to be reckoned with, far-sighted, driven by values of social justice and equality, a wise adviser, kind, reflective, funny, humble, sensitive, rock steady and lovable. The funeral was, of course, in Sheffield, his adopted home, for his career was defined by municipal rescue of the city. When he took over as chief executive, in 1997, the council was in crisis, crippled with debt. This was a depressed city, losing its identity without steel. Eleven years later, after much ruthlessness in city hall, it was almost unrecognisable, its centre revived with squares and plazas, covered winter gardens, a refurbished city hall, new hotels and housing; public money levering in private investment, unemployment cut. He left it rated four stars by the now defunct Audit Commission, a showcase for what good councils can do. His story is full of lessons in good governance. It was the then cabinet secretary, Gus O’Donnell, who plucked him out to be permanent secretary at the Department for Communities and Local Government, one of a cadre of local authority executives O’Donnell brought into Whitehall. The fresh air of local authority experience was what Whitehall needed then, and now. Unlike civil service lifers, council chief executives actually run services: everything from bins to care, nurseries to planning, all in real time on the ground, not from policy theory. They already have that essential experience of working closely with the politicians in their councils, parties in power changing at elections. How did this infusion of new blood go? Rob Whiteman was another O’Donnell recruit, a former chief executive of Barking and Dagenham, brought in to run the UK Border Agency. Other chief executives recruited included Carolyn Downs of Brent, Helen Bailey of Sutton and Lin Homer of Birmingham city council, David Henshaw of Liverpool. “The Whitehall organ rejected us,” says Whiteman. “Its antibodies attacked us. You don’t last there if you come in late from somewhere else. Most of us didn’t last all that long. The civil service sees you as inferior – not policy people like them, but practical.” He talks of unconscious snobbery: “I still talk like where I come from, a two-bed flat in the East End. Bob didn’t talk quite like them either, so the Oxbridges think you aren’t as clever as them.” Kerslake kept his native Somerset burr. He lasted as head of the civil service from 2011 to 2014. “I’m afraid I gave Bob a poisoned chalice,” O’Donnell tells me now, “because David Cameron decided to split my job, which I always said was a very bad idea.” Jeremy Heywood, as cabinet secretary, kept the prime ministerial ear; Kerslake was left responsible for everything in Whitehall departments battered by austerity and staff cuts. Naturally, Heywood succeeded in elbowing him out and taking back both roles. There is a lesson to be learned, says Prof Tony Travers of the London School of Economics. “There should be two-way traffic. Civil servants should be sent out to councils not as exile but as their career path, easily returning later to Whitehall. It would break that closed culture, and teach them about running services.” There’s no room here to list the phenomenal portfolio of councils, charities, commissions and agencies Kerslake ran. He knew how to be the good civil servant, working with Eric Pickles and Francis Maude, to their high praise. When Jeremy Corbyn needed someone to sort his chaotic office, Kerslake was glad to help, and to prepare his team for office, as he would have taught anyone the mechanics and skills of government. That is why, shortly before his death, and following Dominic Raab’s graceless resignation after a damning report on black-belt-level bullying, accompanied by similar complaints of maltreatment by other ministers, he wrote a robust defence of the civil service. Civil servants were not “passive aggressive”, or “snowflakes”, or a “fifth column” out “to frustrate and obstruct the government’s policies”; rather, they served governments, he wrote. However: “Serving a minister well means giving them honest advice, even when it is not always welcome.” That’s been the problem, their problem, our problem. A decade of what Whiteman calls “lower grade” ministers, making policies not designed for implementation but for public effect. “They make unachievable policies and they don’t want to listen. Maybe they should bring in all their own officials and advisers, who depart with them, US style,” he says. Of course civil servants have political and policy views, and the service always needs improvement. But if only true believers are trusted, politicians in revolving doors between ministries lose that collective knowledge and wisdom. We all lose when that happens. Kerslake was the system at its best. Let a truly diverse, truly adaptable and, once again, truly respected civil service be his legacy. Polly Toynbee is a Guardian columnist