Ethiopia is only one of 20 or more African countries where land is being bought or leased for intensive agriculture on an immense scale in what may be the greatest change of ownership since the colonial era.

An Observer investigation estimates that up to 50m hectares of land – an area more than double the size of the UK – has been acquired in the last few years or is in the process of being negotiated by governments and wealthy investors working with state subsidies. The data used was collected by Grain, the International Institute for Environment and Development, the International Land Coalition, ActionAid and other non-governmental groups.

The land rush, which is still accelerating, has been triggered by the worldwide food shortages which followed the sharp oil price rises in 2008, growing water shortages and the European Union’s insistence that 10% of all transport fuel must come from plant-based biofuels by 2015. In many areas the deals have led to evictions, civil unrest and complaints of “land grabbing”.