African innovators celebrated by Royal Academy of Engineering

The prize - which is claimed to be Africa’s biggest award for engineering innovation - was established to stimulate innovation in sub-Saharan Africa and covers all disciplines from mechanical, civil and computing to biomedical, oil and gas, mining and electronic engineering.

The four finalists include South African engineer Ernst Pretorius, who has developed a fence-mounted security that warns owners of fires or intruders and Tanzanian engineer Dr Askwar Hilonga whose sand-based nanofilter is able to remove a range of contaminants from water rendering it safe to drink.

The other two finalists are Zambian innovator Musenga Silwawa, who has invented a fertiliser applicator, that offers an alternative to manual fertilser application for small-scale farmers and a Kenyan team led by Samuel Wangui for their work on Chura, a SIM-card-swapping mobile application that allows users to jump between two different SIM cards and send airtime across mobile carriers.

The overall winner  - who will be awarded £25,000 - will be chosen after the finalists present their engineering innovations and business plans to the judges at a ceremony in Cape Town later this year. Each runner up will receive £10,000.