From 1870 to 1914 the Basel Mission succeeded in extending its work from the Akwapim Ridge to Kwahu, Akim and Asante and across the Volta as far as Yendi the north in 1913.
During this period, difficulties encountered were different from the initial difficulties which will more related to sickness, deaths and the suspicion of indigenous people in accepting the Gospel. Now, with the burgeoning Cocoa industry, the expansion of commercial activity, the development of gold mines and the building of roads and railways disturbed the traditional lifestyle. This decreased the zeal with which people began to accept the Gospel leading to nominal Christianity. Moreover, the Islamic religion was also being introduced to the southern section of the country by Muslim immigrants from the north of the colony.
In spite of all this, with the advent of the First World War in 1914 in the Kwaku District there were 21 congregations with a total of over 2500 members. The Akim area had about 3400 converts over 32 villages and there were about 900 children distributed in 27 Schools. The Basel Mission, as a result of this phenomenal expansion trained many local personnel to man the new stations.
After World War I was declared in 1914, the German missionaries were restricted in their movements by the British in the British colonies. The restrictions intensified until in the second week of 1917, when all German missionaries were rounded up, brought to Accra and deportations began on December 16. The work of the Basel Missionary Society was taken over with the consent of the Basel Mission Home Board by the United Free Church of Scotland whose ecclesiastical organization was Presbyterian. The Scottish Missionary Society had been working in Calabar, Nigeria, also a British colony adjacent to the Gold Coast and it was from the Calabar Presbyterian Church in Nigeria that a missionary was sent to take charge of the Presbyterian work in the Gold Coast after the deportations.
This was a bitter pill for the Basel Mission to swallow after 19 years of devoted service in the mission field in the Gold Coast but they were not dismayed when they considered that “in education and agriculture and artisan training and in the development of commerce, and medical services and concern for social welfare of the people, the name Basel by the time of expulsion of the mission from the country, had become a treasured word in the minds of the people”.
By February 2, 1918, all Basel missionaries had been deported from the Gold Coast.