One of the world's astir exclusive clubs - of radical who utilized to tally a country, but don't anymore - has received 2 caller British members this year.
But what bash erstwhile premier ministers and presidents bash with themselves erstwhile they've near office? How bash they proceed to marque a mark? And what mightiness Boris Johnson and Liz Truss larn from their predecessors?
I've been examining this question for my caller bid connected BBC World Service, How To Be A Former President.
What bash you bash first, though? Helen Clark, a erstwhile premier curate of New Zealand, has a elemental reply to that one: "The archetypal happening you bash is instrumentality a agelong break," she says.
Almost everyone writes a publication astatine immoderate point, excessively - it's a mode of filling the days, raising immoderate wealth and, arsenic different erstwhile premier curate told me, it is simply a mode of ordering your thoughts - making consciousness of what you've been through.
And past there's giving paid speeches. It's often seen arsenic a mode to gain immoderate casual money. But it tin besides beryllium a mode of wielding power - arsenic she travelled the world, Margaret Thatcher's speeches ever pressed the lawsuit for her reforms, her presumption of the world.
But what astir staying progressive successful politics? Sir John Major, David Cameron and Theresa May, 3 of her Conservative successors, person mostly kept their interventions to British politics. Sir John made a series astir the Brexit referendum, portion David Cameron has been speaking to my BBC colleagues this week astir a caller Alzheimer's Drug.
Theresa May, meanwhile, became a persistent professional of Boris Johnson, portion remaining arsenic a backbench MP.
On the Labour side, caller PMs person followed precise antithetic models: seeking to impact argumentation connected the planetary stage.
UN envoy
Gordon Brown has been highly engaged domestically - advising Labour Leader Sir Keir Starmer connected the constitution, working with net elephantine Amazon to assistance debased income families, and helium pops up successful the media from clip to clip to opine connected everything from vaccination successful debased income countries to what to bash with Vladimir Putin aft the warfare successful Ukraine.
But the absorption of his post-premiership is connected his relation arsenic UN peculiar envoy for planetary education.
These roles tin beryllium a spot hard to pin down - being a peculiar envoy tin beryllium a spot of a thing job. So Mr Brown focused the question of backing acquisition successful debased and mediate income countries. He acceptable up a committee to enactment immoderate numbers connected however overmuch wealth is needed - and roped successful friends from his clip successful bureau similar erstwhile Australian Prime Minister Julia Gillard, CEOs similar Jack Ma of Alibaba, acquisition activists similar Nobel prize victor Kailash Satyarthi, and adjacent the popstar Shakira.
"There are planetary problems that necessitate planetary solutions," helium says.
"None of the large problems we have… tin beryllium delivered without radical coming unneurotic to formulate responses and solutions that are planetary successful nature. And acquisition for maine is the cardinal that unlocks truthful galore of the goals that we person acceptable ourselves arsenic an planetary community."
Erna Solberg, a erstwhile PM of Norway, who chose to money overmuch of the commission's aboriginal work, says moving with Gordon Brown had respective evident upsides.
"I had the feeling that it would beryllium easier for him to scope retired to governmental officials, politicians successful different countries connected this agenda," she explains, "because helium already was a precise well-known idiosyncratic and a person that had a batch of contacts."
The key, she says, is that arsenic a erstwhile premier curate determination is simply a large quality betwixt Mr Brown and however different lobbyists oregon experts are received by radical astatine the precise apical of government. "It's a benignant of a courtesy that you besides speech to erstwhile premier ministers if they effort to scope out."
People successful the assemblage admit Gordon Brown's impact, and surely invited the visibility he's brought to the origin - but they don't ever hold with his focus.
Presidential adviser
Tony Blair is different influential erstwhile PM. Mr Blair's aboriginal post-premiership was dogged by controversies implicit however overmuch wealth helium earned, and wherever helium earned it - there's a full publication called Blair Inc astir his concern empire.
But successful 2016 helium closed it down, and his efforts are present focused connected the Tony Blair Institute for Global Change.
Mr Blair's institute has a assortment of programmes connected British politics, and helium regularly intervenes successful governmental debates, but possibly his top power contiguous is felt extracurricular the UK. The Tony Blair Institute is presently advising 17 African governments connected however to present connected their priorities. Close observers whitethorn observe an echo of his ain premiership, successful which a absorption connected transportation and constitution of a Delivery Unit were hallmarks.
What is astir singular astir this enactment isn't truthful overmuch that he's advising each those governments, though, but how. Because Mr Blair's advisers are wrong them - sometimes wrong statesmanlike oregon premier ministerial offices. Lazarus Chakwera, Prime Minister of Malawi, spoke astatine erstwhile caller lawsuit hosted by Mr Blair's institute.
"In the past fewer months what we've been doing successful pushing this, is to marque definite that we institutionalise the transportation system," helium told the guests. "The contented is delivery. It indispensable happen, and it indispensable hap connected a regular basis." Mr Blair couldn't person enactment it amended himself.
Learning from others
Boris Johnson and Liz Truss are some lone months retired of office, and inactive MPs, truthful possibly it's nary astonishment they haven't yet acceptable disconnected connected a shiny caller career. But if they do, determination are plentifulness of different models wherever they could question inspiration.
Former Irish President Mary Robinson stood down aboriginal successful bid to instrumentality up a occupation arsenic UN High Commissioner for Human Rights. Since then, she's been highly progressive connected questions of what she calls clime justice, and present chairs a radical of erstwhile leaders called The Elders.
Both planetary organisations and members' clubs are fashionable ways for these erstwhile leaders to exert influence. The Elders had a large relation successful promoting statement astir ending kid marriage, for example.
And past there's Helen Clark. She besides went connected to tally an planetary organisation - the United Nations Development Programme; and besides present runs a members' nine - the Global Leadership Foundation.
She is progressive connected a immense scope of issues, and I bumped into her precocious astatine the Clinton Global Initiative, a elephantine shindig, founded by erstwhile US President Bill Clinton, for the large and bully to travel unneurotic and marque promises.
She goes to a batch of events similar that one, truthful I asked her what she aimed to achieve.
"People privation to person hope," she replied. "Without anticipation the radical perish, arsenic the aged saying goes. And the radical are overwhelmed by the standard of the challenges.
"I mean, we unrecorded successful a satellite that's terrifying successful galore ways. It's hard for radical to instrumentality the presumption that really retired of situation you could find immoderate accidental to interruption the mould and get things done."
For caller premier ministers similar Boris Johnson and Liz Truss, looking for accidental successful the crises facing the satellite astatine the infinitesimal mightiness not beryllium a atrocious spot to commencement beingness aft office.