I lived for the sake of this country, Hosni Mubarak told Egyptians as he desperately clung to power last week. But in truth his country lived for the sake of its leader: he, his family and his friends fleeced the nation, diverting billions into secret bank accounts and properties in the most exclusive areas of London and Los Angeles.

One estimate in the Guardian – reflected back to the world in banners in Tahrir Square – put the scale of his family's theft at an astonishing £43.5bn. So while a quarter of Egyptians are bought up in poverty, the president's son has amassed a portfolio of assets worth an estimated £10.5bn, including a five-storey Georgian house in London's Knightsbridge. Little wonder there was such anger on the streets.

Now it has emerged that Britain's Serious Fraud Office is looking into any assets Mubarak and his family may have stashed away in this country. Better late than never, I guess, but this is far from an isolated case. After Ben Ali was chased out of Tunisia, it turned out he had plundered an estimated £3bn from his country's coffers. One of the first WikiLeaks cables alleged the president of Sudan, Omar al-Bashir, siphoned off $9bn from his country's oil boom, much of it hidden by helpful British banks. In France, three African leaders and their families face accusations of embezzling state funds and buying trophies such as penthouses and Ferraris valued at £137m.

Our standard response to these tales of grand larceny is to shrug our shoulders and deplore corruption in the developing world. Corruption is corrosive, eating away at countries from within. It is thought to cost African states one-quarter of their GDP each year and to push up the price of goods by one-fifth. In Kenya, nearly one-third of people's wages is estimated to disappear into the pockets of corrupt officials.

But as the big men steal and their people suffer, we are aiding and abetting their crimes. So instead of just applauding Egypt's protesters, we should take responsibility for our own contribution to their poverty and unemployment. This would do far more to help the developing world than our obsession with aid. So let's end the hypocrisy.

First, we need to crack down on companies that bribe their way to deals and contracts around the world. Britain lags behind other developed countries to such an extent that the OECD is threatening to blacklist UK exporters. Sadly, the government has just delayed a new anti-bribery law for the second time, giving in to the business lobby's squeals.

This proposed legislation marked the first major reform in this area for more than a century and was the result of detailed cross-party work over several years. It would go some way to restoring Britain's reputation after the scandalous decision of the Blair government to allow the abandonment of an investigation into BAE's arms deals. The delay harms the interests and image of our country.

But it should be only the first move. All these hideous rulers ripping off their people need help to hide their plunder. In Britain, as elsewhere in the west, bankers, lawyers and accountants are living off immoral earnings by laundering this money. They should be forced to stop acting like pimps, as one leading economist calls them. We have introduced tough measures to prevent terrorists moving money around the globe, so why not for these thefts, which lead to the deaths of far more people? The regulatory flaws allow financiers to do business with some of the world's biggest crooks and play a key role in keeping nations impoverished.

We should seize the moment to ensure the global banking system is forced to trace, freeze and return these vast stolen sums – and that the next generation of despots find it much harder to steal and hide their people's money. Only then would our support for the protesters in Tahrir Square be more than platitudes.