Britain became involved in Africa in the late 19th century mainly for economic reasons as it had vast supplies of raw materials and it allowed British markets to expand. There were however political and strategic interests which acted as trigger actions, changing Britain’s empire in Africa from a formal one to an informal one.
British interest in Egypt began mainly due to economic and political reasons. Lord Palmerstone himself claimed in “What we wish about Egypt is that it should be attached to the Turkish Empire, which is security against it belonging to another power. We wish to trade with Egypt”.  Britain wished to be trading partners with Egypt, as Egypt was a producer of very high quality cotton. (Hobson) In order to protect these trading interests, Britain wished for Egypt to remain part of the Ottoman Empire and not fall into the hands of the French, Britain’s rival power which also had economic interest in the area.
The construction of the Suez Canal in 1869 attracted huge amounts of British investment in the form of loans used for economic development. Britain had particular interests in the Suez Canal as it provided a quick route to India, one of Britain’s most important trading partners. This led to a huge economic crisis as Egyptian debt rose from £3 million in 1863 to £100 million in 1879. 
It was the Egyptian uprising of 1881 which triggered Britain’s formal control over Egypt. The Anglo-French dual control over the economy led to social unrest and therefore street rioting. Britain invaded and crushed the rebellion in October 1882 and it was left in formal control over the whole country. Britain’s initial interest was trade and loans to the country. The uprising was used as a trigger to seize the country and make it part of the British Empire. Furthermore Britain wished to remove French control as they feared this would affect trading interests.
Britain’s initial interest in West Africa was also due to economic factors. (Hobson) British government had no interest in colonial expansion since in 1865 a Parliamentary select committee suggested no further colonial expansion should take place in the area. West Africa was however of particular interest to British traders and investors, such as George Goldie, as it was a large source of palm oil. Palm oil was used as an industrial lubricant and a key component in the manufacture of soap, a thriving industry at the time. George Goldie had a monopoly over the palm oil trade around the river Niger and formed the “Royal Niger Company”. The fact that Goldie expanded inland without government approval suggest that initial expansion was purely of economic interests of George Goldie, a man on the spot.
It is however the involvement of foreign powers which attracted interest from the British government. The French moved inland from Senegal and in 1182, King Leopold of Belgium set up the Congo Free State and a successful rubber industry. This Belgian involvement caused the French to move inland from Gabon to create the French Congo. The overall situation grew worse as Germany seized Togoland and Cameroon. This large foreign involvement led to the treaty of Berlin being signed in 1885, giving European powers formal control of territory in Africa and free trade in the Congo Basin. Britain’s economic interest in Niger was recognised and Britain was left with a monopoly over the palm oil trade. It is therefore trade, and the protection of trade from foreign powers that caused the scramble for West Africa.
The British government was worried that if they did not act, the France would have expanded their West African empire, interrupting Britain’s important trade links.
Britain’s involvement in East Africa initially began with economic interests. The island of Zanzibar imported huge quantities of manufactured goods from India and Britain, such as British steel. The total import and export trade measured at £2 million. British involvement was driven by Sir William Mackinnon, a British trader, who set up the British East Africa Company in 1888, backed by investors such as James Hutton, a cotton manufacturer from Manchester. British trade in East Africa was said to have huge economic potential for future development without formal colonisation and involvement from the British government. (Robinson and Gallagher)
It was however the defence of trade and international rivalry which prompted involvement from the British government. The arrival of Karl Peters, a German explorer who started the German East Africa Company caused the largest problems. He was backed by the German chancellor, Otto Van Bismarck and was able to seize the area of Tanganyika. Britain’s greatest fears were the creation of a German naval base of the East coast which might have threatened British links with India.  The fears caused by this foreign involvement prompted Mackinnon and other British traders to put pressure on the British government for assistance.
To prevent further German expansion and to protect trade, an agreement was made in 1886, leaving Germany with Tanganyika and Britain with Kenya and Uganda. The eventual bankruptcy of the East Africa Company left the government in formal control of a largely unwanted East African Empire. As with the example of West Africa, the scramble for East Africa was mainly due to interests in trade and protecting trade. There were also strategic interests in the area as Britain wished to prevent a naval base from being built on the East Coast.
The partition of Southern Africa was mainly due to two factors: the ambition of Cecil Rhodes and Anglo-Boer Rivalry. Rhode’s was a British multi-millionaire who arrived in South Africa in 1870. His main interest was economic and he quickly made a large fortune from diamond mining. Rhodes saw South Africa as an opportunity to expand his own personal wealth due to the vast amount of precious materials in the area such as diamonds and gold. (Lenin) In 1886, a gold mine was discovered in Transvaal, which attracted interest from many uitlanders, including Cecil Rhodes. Rhodes sought to ally with the Rothschild bank to attempt to gain a monopoly over diamond production in the South. The treaty of London in 1884 recognised the independence of the Transvaal however Britain was left in charge of it foreign policy, allowing it to benefit economically from it. 
On the other hand Cecil Rhodes many have been interested in Southern Africa due to patriotic reasons and Imperialism. He was incredibly racist: “I contend we are the first race of the world and the more of the world we inhabit; the better it is for the human race.”  An example of his patriotism was that he had a dream that the whole of the African continent would be under British rule. There would be a railway line linking the Cape to Cairo. Further factors include protection of the Boers in the Transvaal. The Boers asked for British help in 1877 against the Zulus.
Britain used this event as a trigger action to take the opportunity to consolidate rule in Southern Africa. Furthermore, Britain wished to protect its control from other foreign powers such as Germany. In 1884 there was a possibility of a German-Boer alliance which was of great concern to Britain. The 1884 Treaty of London allowed Britain to restrict German-Boer links as they seized control over Transvaal foreign policy.
The diamond and gold mines are what attracted British interest in Southern Africa, mainly from Cecil Rhodes. It was the involvement of Boers and the Boer wars which triggered Britain to expand colonially through Southern Africa.
Overall the main cause of the scramble for Africa was mainly a result of economic factors. Britain was in an economic depression from 1873-1879 and it wished to expand to new markets. (Platt) Africa was extremely rich is raw materials and resources. There were however a number of events, mainly the involvement of foreign European powers which resulted Britain in wanting to protect its trade interests and preventing these powers from seizing control over Africa.