Now Britain has made Rishi Sunak its latest ex-prime minister, it’s time to rethink the role. The antics of former PMs have helped send trust in politics to all-time lows. We’ve seen Tony Blair shilling for autocracies, David Cameron lobbying for Chinese interests and for the collapsed financial firm Greensill Capital, Boris Johnson meeting Venezuelan dictator Nicolás Maduro on behalf of a hedge fund manager, and Liz Truss giving embarrassing but well paid speeches to rightwing American audiences.

The sight of the country’s best known politicians renting themselves out to dubious clients is the most vivid possible symbol of ruling class corruption. Keir Starmer could buy himself initial goodwill and do Britain a favour by setting limits to his own future role.

Former PMs seldom caused trouble before the 1970s. Back then, most of them had family money. They would never do anything so vulgar as consult for Kazakhstan or speak at a Trumpist conference in Maryland, even had such opportunities existed in their day. As Private Eye summed things up in 2016:

“Harold Macmillan became an active chancellor of Oxford University and bequeathed a six-volume autobiography to a grateful nation; Sir Anthony Eden took a similar post at Birmingham University and bred Hereford cattle, while Sir Alec Douglas-Home ran a cricket club and pottered around on the Scottish family estate … Clement Attlee retired to the Lords at 72, while Harold Wilson, cashing in on his supposed wit, tried his hand as a chatshow host with no joy.”

The monetisation of the role took off with Ted Heath, who advised entities including a Chinese state-owned shipping company and a thinktank created by a Saudi sheikh – jobs he didn’t declare while remaining an MP. After her ousting, Margaret Thatcher consulted for the tobacco company Philip Morris, giving advice on how to lobby MPs.

The problem worsened with the boom in foreign autocracies rich enough to buy a British ex-PM. Blair helped out multiple tyrants, including advising Kazakh dictator Nursultan Nazarbayev on how to spin the killing of anti-government protesters. (The message was that the protestors’ deaths, “tragic though they were … should not obscure the enormous progress that Kazakhstan has made”.) After Brexit, Cameron schemed to set up a UK-China fund that would raise $1bn to invest in projects in both countries. Fuelled by a dinner with Chinese leader Xi Jinping in 2018, he attempted to persuade the China Investment Corporation, the state’s sovereign wealth fund, to inject hundreds of millions of pounds. In short, it seems he was trying to go into business with the Chinese government. Last year he was urging investors to put money into Colombo Port City, a project in Sri Lanka that was part of the Chinese state’s global infrastructure strategy, when, no doubt to Beijing’s delight, Rishi Sunak made him foreign secretary.

The problem of what to do with former PMs has now reached crisis levels, especially because, as Gordon Brown recently noted: “the Conservative party seems to have found the magic formula for the mass production of ex-prime ministers”. Moreover, ex-PMs keep getting younger. Johnson, Truss and Sunak could be monetising the office for decades. American audiences in 2060 might still be hearing about how “trans activist” civil servants wrecked Truss’s brilliant premiership.

Being PM has become a CV-burnishing temp role, a trampoline to seriously paid gigs. Each new entrant into Downing Street is effectively handed a multimillion-pound cheque they can start cashing the day they are kicked out.

Any system rots from the head. A nurse, civil servant or police officer reading about ex-PMs’ self-enrichment could be forgiven for thinking: “Clearly we’re not all in it together. I’ll never be able to buy a home, I’m struggling to feed my kids, I’m earning less than I did in 2010, I’d be a mug not to take anything myself.”

It needn’t be like this. Not every politician is grasping. John Major, for instance, chose his post-power gigs using the test: “How would this look on the front page of a newspaper?” He and Theresa May showed it was possible for former prime ministers to enrich themselves in fairly innocuous ways. Major became European chairman of the Carlyle Group, a private equity firm. He and May also got rich giving boring but harmless talks on the speaking circuit.

Brown appears not to have enriched himself at all. His fees for advising the international fund-management firm Pimco and a Swiss private equity firm were reportedly paid to the Office of Gordon and Sarah Brown, the organisation that supports the couple’s charitable work.

These people provide a working model for how to be an ex-PM. Former prime ministers already receive generous state pensions, and can claim up to £115,000 a year for office and secretarial costs. Let them also write books, work for charities and media, and give paid speeches in approved countries (broadly: democracies).

Beyond that, the state should constrain their activities. Ex-PMs should be made to wait perhaps a decade before they can do consulting work for companies – bearing in mind that “consulting” is often a euphemism for lobbying, or for identifying the right people to lobby in government. Each new PM would have to sign a legally binding contract accepting these terms. If that deterred grasping people from seeking the premiership, then fine. These free measures would instantly attract a better class of person to the job, reduce corruption, deflate populism, keep experience inside government, and do PMs a favour by preserving their reputations from their own greed.

We should start treating our ex-prime ministers as national assets. Leaving aside duds like Truss and Johnson, they could act as a brains trust with the unmatched knowledge that comes from running a state. Once Major had returned to the backbenches, whenever he spoke in parliament on Northern Ireland, MPs actually listened. Blair’s network and his understanding of international politics could have been of particular benefit to Britain. What a pity it was sold to tyrants.

Good Chaps: How Corrupt Politicians Broke Our Law and Institutions – And What We Can Do About It by Simon Kuper is published by Profile.

Further reading

How They Broke Britain by James O’Brien (Ebury, £10.99)

The Impossible Office? The History of the British Prime Minister by Anthony Seldon with Jonathan Meakin, Illias Thoms and Tom Egerton (Cambridge, £14.99)

The Establishment: And How They Get Away With It by Owen Jones (Penguin, £10.99)