Jeremy Clarkson and Richard Hammond tackle the twin problems of an ageing population and the increasing complexity of modern cars. Their solution is to design a vehicle exclusively for the elderly and then test it out in Dorset with a little help from a trio of pensioners.

James May assesses the new Range Rover around London and then shifts to Nevada for the ultimate challenge against an autonomous military machine. Plus actor James McAvoy is the star in the Reasonably Priced Car.

In the second part of the Top Gear special, Jeremy Clarkson, Richard Hammond and James May continue their epic African odyssey.

Having survived insane traffic, lethal mudslides and some distinctly dubious map reading, the trio and their ailing estate cars reach the climax of their quest to find the definitive source of the Nile.