Oxfam is calling for urgent action to stop international investment firms turning people in poor countries off their land. The charity warns that rising food prices and the value of agricultural land has led to unprecedented "land grabs" in the developing world.

It says nearly a third of Liberia has been swallowed up by land deals in just five years, and areas equivalent to the size of London are being leased or sold every six days.

Oxfam is urging the World Bank to temporarily freeze all its land investments and wants the British government, which takes over the leadership of the G8 next year, to take action on the issue.

The Today programme's Mike Thomson reports on the impact on the price of and demand for land on poor farmers.

Get in touch with Today via email , Twitter or Facebook or text us on 84844.