Gordon Brown has begun his trip to Africa with a visit to a primary school in Kenya.

The chancellor kicked-off his week long journey on Wednesday in which he is set to see for himself the need's of the world's poorest continent.

With the largest part of Britain's £18.7 million annual aid to Kenya going into education he told school children in the Kibera slum he wanted to observe the impact of the spending.

With Britain holding the presidency of the G8 group of industrialised nations this year, Brown is set to play a key role in the government's plans to encourage wealthy countries to radically increase their aid and development budgets.

But the four country trip has been seen as an attempt by the Treasury to take ownership of a large swathe of foreign policy as part of the chancellor's battle with Tony Blair.

Brown was also set to meet with Kenyan President Mwai Kibaki and Nobel Peace Prize winning campaigner Wangari Maathai on Wednesday before continuing his travels in Tanzania, Mozambique and South Africa.

As a member of the prime minister's Commission for Africa he will hold talks on his plans for an international finance facility for developing nations and his call for an increase in aid of half a trillion dollars from the G8, if the UN's Millennium Development Goals are to be met.

A Treasury spokesman said: "This will be an important opportunity both for the chancellor to raise the profile of the government's priorities for our presidency of the G8, and for him to see at first hand why it is so vital to pursue them.

"It is also an opportunity for the chancellor to meet and talk to a wide range of African people about their views - from presidents and prime ministers to aid workers and schoolchildren."