Britain is back in Africa: with renewed pledges of troops on the ground.

Theresa May’s speech to the United Nations talked of an “increase” in what is termed “security support.”

But the reality is a considerably wider military engagement.

Briefings to the British press gave an indication of what is to come: more than 100 troops  deployed to Somalia to fight al-Shabaab.

The UK forces will be joining troops from Ethiopia and Kenya (each of whom have their own domestic agenda in Somalia) and soldiers from Uganda and Burundi.

Becoming bogged down in the quicksand of Somalia is a real risk. Britain has a long history of fighting in the region, going back to before the First World War, when its troops attempted to crush the “Mad Mullah” – Sayyid Mohammed Abdullah Hassan – for more than two decades.

There will also be an additional £80million to help provide 30,000 jobs in Ethiopia. Most of the money will go to help find work for the thousands of Eritrean refugees who pour out of the country every month, in an attempt to escape a tyrannical regime.

Other money will go to help Somalis return home from the giant Dadaab refugee camp in northern Kenya that is home to 350,000 people. The Kenyan authorities have been threatening to close the camp for many months, and appealed for cash. Theresa May called President Kenyatta earlier this month to discuss security concerns, and this issue will have been part of the conversation.

These initiatives come together with plans to send 400 British troops to bolster the UN in South Sudan.  Although they look like isolated decisions they form part of a wider, more muscular, British strategy.

The aim is to try to halt the exodus of African refugees struggling to cross the Sahara, arriving on European shores and finally making their way to Calais. While it addresses a clear humanitarian need, the agenda is essentially driven by UK domestic concerns.

It is a policy which attempts to stabilise crises as close as possible to their source; engages with African governments, no matter how brutal, and uses the British aid budget to enhance the military effort.

Much of this is entirely sensible. International aid workers will be very reluctant to return to the South Sudanese capital if they continue to face threats of brutal attacks, including rape.

But it runs into two clear objections.

The first is that it involves working with some of Africa’s most repressive dictatorships. The New Statesman has tracked the evolution of this strategy, which was developed at an EU – African summit in Malta in November 2015.

Relations with regimes including Eritrea and Sudan, involving links with police and security forces, are part of this programme. This is currently being led by the German government and is designed to keep African migration at bay.

The second issue is the diversion of the British aid budget for military purposes. This has been outlined by the new development Minister, Priti Patel. No friend of international aid, she signalled via the Daily Mail that the aid budget would in future deliver for the “national interest.”

As she told the paper, in future this would involve “Pouring hundreds of millions of pounds into foreign hotspots to deter ‘mass migration’ to the UK and mainland Europe.” Whether this expenditure meets agreed international aid criteria is beside the point, from Ms Patel’s perspective.

It is this combination of British soldiers in African hotspots, co-operation with African despots and the muddying of the aims of the aid budget that are the bedrock of the current policy.

From Royal Navy operations off the coast of Libya, to tracking migration routes via South Africa, the objective is to halt the flight of Africans.

As Mrs May knows from her many years in the Home Office, this is among the most toxic questions she faces: it is a personal priority for her as Prime Minister.