AFRICAN leaders don’t so much step down as run away. Idi Amin’s infamously brutal reign in Uganda, which led to the deaths of an estimated 300,000 people, came to an end in 1979. He fled to Saudi Arabia and died there in 2003. Mobutu Sese Seko seized power in mineral-rich Congo in 1965. After 30 years of profoundly corrupt dictatorship he was overthrown and took refuge in Morocco. Gambia’s Yahya Jammeh ruled for more than 22 years. Last year, the opposition candidate was elected to replace him, resulting in a tense stand-off. Eventually, Mr Jammeh and his family flew into exile in Equatorial Guinea.

They don’t all get away with it, or at least not any more. Chad’s Hissène Habré was forced out in 1990 and lived in luxury for two decades in Senegal. He was then seized by paramilitary police, tried in a court specially set up by the African Union, and in May was sentenced to life in prison for war crimes, torture, and sex crimes – the first conviction of a former head of state by an African court for crimes against humanity. Charles Taylor was president of Liberia during a civil war that killed more than 250,000 people. He split for Nigeria in 2003, but was extradited to face charges at a UN-supported Special Court and is now serving a 50-year sentence in Durham Prison.

What will be the fate of Robert Mugabe? The doddery tyrant is, at the time of writing, refusing to resign as President of Zimbabwe, but last week’s military takeover means his 37-year reign is over: the Zanu-PF party has sacked him as leader and is threatening to impeach him unless he quits. Will the 93-year-old be allowed to see out his days in style in Harare, or will he become the latest demagogue to jump into the arms of a friendly foreign despot? And then comes a more important question: will his likely replacement, Emmerson Mnangagwa, be an improvement? The desperately sad answer is very probably not. In late 2000, a cable written by a US diplomat described Mr Mnangagwa as “widely feared and despised throughout the country”, and warned he could be “an even more repressive leader”. As head of the Zimbabwean secret police, the Central Intelligence Organisation (CIO), he was involved in massacres of the Ndebele ethnic group in Matabeleland, a region opposed to the Mugabe regime. At least 20,000 civilians were killed by the CIO and the armed forces, and most were shot in public executions, often after being forced to dig their own graves in front of their families. The Labour MP Kate Hoey, a long-time campaigner against oppression in the state, has described Mr Mnangagwa as “probably the one person in Zimbabwe who inspires even greater terror than Mugabe”.

The failure of political leadership in Africa is a deep and enduring tragedy. In 2007, the Sudanese-British billionaire Mo Ibrahim set up the Ibrahim Index of African Governance (IIAG) to monitor countries’ performance across four main measures: safety and the rule of law, participation and human rights, sustainable economic opportunity, and human development. Its 2017 report finds that while the majority have improved overall governance over the past decade, the progress of more than half has now begun to either slacken or even reverse. More governments are involved in armed conflict, infrastructure development is patchy, and the vast continental rural economy is struggling. Progress on education has almost ground to a halt.

In the year the index was launched, the famous Ibrahim Prize was also created. It is intended to be awarded annually to a democratically elected African head of state or government who has left office voluntarily within the past three years, having improved the lot of the country and its people. The winner receives a $5 million initial payment, plus $200,000 a year for life, the most generous award of its kind. In 10 years, the panel has only been able to identify a deserving individual on four occasions, and has announced no winner on the other six.

This matters, and not just for humanitarian reasons or the hygiene of our own souls, important though those things are. Africa is not a far-away place of which we know little. Its democratic and economic improvement is central to our own societies’ fortunes and will only become more so in the future. For a start, failing and corrupt states are a major drag on global economic progress. They are also more likely to collapse into civil war, consuming vast amounts of international diplomacy, disrupting trade patterns and sometimes stoking radicalism on our own shores. Russia and especially China have energetically been building alliances that enable them to exploit the continent’s large, untapped reserves of minerals, oil and gas. There’s an obvious geopolitical game being played.

By 2050 at the latest, Africa will have the largest youth workforce in the world, likely coupled with mass youth unemployment – a situation which, as we saw with the Arab Spring, is a powder keg. The struggle against radical Islam depends on keeping the disaffected young out of the grip of movements such as Islamic State and al-Qaeda.

And, of course, Africa is extremely vulnerable to climate change, in the form of flooding, drought, the impact on food supplies and malnutrition, the spread of disease and a lack of shelter.

All of these problems are feeding the immigration nightmare that has in part caused Brexit and is sending shockwaves through the rest of the EU. They lead boatloads of the wretched to European waters, where they are often drowned as they seek a better life. The current president of the European Parliament, Antonio Tajani, is predicting an exodus “of biblical proportions… Population growth, climate change, desertification, wars, famine in Somalia and Sudan. These are the factors that are forcing people to leave. When people lose hope, they risk crossing the Sahara and the Mediterranean because it is worse to stay at home, where they run enormous risks. If we don’t confront this soon, we will find ourselves with millions of people on our doorstep within five years.”

We have no shortage of immediate domestic crises, of course. But as Mr Mugabe’s haggard old face once more plays across the TV screens, understand that this, too, is our problem.