Britain's prime minister is visiting Africa for the first time as national leader in a bid to boost trade ties ahead of the United Kingdom's departure from the European Union.

Before the visit, Theresa May took issue with her right-hand man, Chancellor Philip Hammond, when she said from the RAF Voyager aircraft on Tuesday that a no-deal Brexit was a better prospect than leaving the EU with a bad deal.

Reuters reported May said a no-deal Brexit "wouldn't be the end of the world", undermining Hammond's dire warnings in a letter last week that it would seriously damage the UK economy.

After arriving in Africa, May said in a speech in Cape Town that Britain will increase its investment in the continent, pledging 4 billion pounds ($5.2 billion) of extra state investment mainly aimed at creating jobs for young people.

"The challenges facing Africa are not Africa's alone," the BBC reported her saying. "It is the world's interest to see these jobs created."

A more stable African economy and improved work prospects for the continent's young people might benefit the UK and other European nations by stemming the flow of illegal migration.

May said the UK wants to overtake the US by 2022 as the largest investor in Africa among the G7 economies. Britain's direct investment in the continent totaled 42.7 billion pounds in 2016 while the US contributed 44.3 billion pounds, according to the United Nations Conference on Trade and Development.

At the start of her three-day mission to South Africa, Nigeria, and Kenya she said there will be a "fundamental shift" in UK aid, with long-term economic and security challenges prioritized, instead of short-term poverty reduction.

And she took issue with some MPs in her party who have criticized the value for money the UK gets from its Africa aid, noting Britain's overseas aid budget, which rose by 555 million pounds in 2016 to 13.9 billion pounds in 2017, ensured millions of women and children received immunizations and education.

May said, going forward, the UK will offer governmental support to private-sector companies investing in fast-growing countries such as Cote D'Ivoire and Senegal,as well as helping nations on the "frontline of instability", including the Republic of Niger, Chad, and Mali.

During her visit, May will discuss security issues, including the threats from Islamist terror groups Boko Haram in Nigeria and al-Shabab in Somalia.

Her visit is the first to sub-Saharan Africa by a British leader since David Cameron's 2013 attendance at a memorial service for Nelson Mandela.

The Financial Times noted that May had undermined Hammond's warnings about the economic damage of a no-deal Brexit by suggesting Treasury forecasts were "just a work in progress".

Hammond said in his letter to the chair of the Treasury select committee that a no-deal Brexit could cause the UK's gross domestic product to fall by around 8.8 percent and trigger a rise in borrowing to the tune of 80 billion pounds.