By Elizabeth Blunt
On the fringes of the European Social Forum in London, people of African descent are holding their own conference - and discussing how Africa could benefit from their achievements.
Estimates suggest Africans working abroad send home $45bn a year
Suddenly Africa is wooing its exiles.
Some of the continent's best brains, and deepest pockets are in London, Paris or New York, not in Lagos or Nairobi.
Add in all the people of African descent, black Americans, the population of the Caribbean and large parts of Brazil, and Africa has millions of prosperous and influential people potentially on its side.
When the new African Union was drawing up its constitution it made space for these people of African origin; after north, south, east west and central Africa, the diaspora was designated the sixth region of the continent.
Sophie Kalinde, the African Union's ambassador in Geneva, is one of the links with this constituency in Europe.
"It's a big population. You know that the dispersal of the population is such that Africa cannot ignore the presence of its own outside Africa," she said.
Perhaps the real wake-up call came after 11 September, when governments began to make careful records of money movements.
Best estimates suggest that Africans working abroad send home some $45bn a year.
But most of it goes on living expenses for their families; they are less likely than expatriate Indians for instance, to invest their savings back home in Africa.
I asked Ambassador Kalinde what she thought Africa could learn from India, or from that other great success story in mobilising its diaspora - Israel.
"You can learn that you can be small and be very powerful. You can learn that you can defend yourself in the public arena, through debate."
"You can see that India has gone even so far as having nuclear power, and most of the resources are the resources that India has had by being so well organised as a diaspora."
But if African governments want the diaspora's money, they will have to earn it.
Another message to this meeting was that collectively Africans living abroad have real strength.
If they want better governance, more transparency, a more stable investment climate, they should demand it; now they know the demands are backed by $45bn a year, their governments may be more ready to listen.