Prince Harry first saw the Halo trust's landmine clearance in Mozambique three years ago and has witnessed the suffering they cause to soldiers and civilians while with the military in Afghanistan.
Some 16 years after his mother's visit to Angola did so much to raise awareness of the problem, mines are still being laid daily.
As ITV News Correspondent Richard Pallot reports, the prince's private visit makes the cause very public once again.
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Among those expected to attend the ceremony will be former US President Bill Clinton and ex-Northern Ireland first minister Peter Robinson.
Five people have been killed and 40 injured after a car and knife attack in London on Wednesday.
A wet, wintry night in places with rain and hill snow slow to move away from southern Scotland and northern England.