Prince Harry's trip to Angola comes 16 years after his mother, Princess Diana, gave the landmine clearance cause a global profile with a visit to the African country.
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.
The Halo trust said "excellent progress" has been made between Princess Diana's visit to Angola in 1997 and Prince Harry's trip this year, but there are "many years of work to be done".
The Halo Trust has said Prince Harry's support to help remove landmines from African nations plays "an invaluable role" in raising awareness of the charity's "work and mission".
The organisation's projects in war-torn countries clears the ground for some of the world's most vulnerable people to plant crops, rebuild homes and raise families in safety.
Prince Harry has expressed his frustration that countries which supplied landmines to African countries are doing nothing to get rid of them, following a visit to clearance projects in Angola.
The 28-year-old followed in his mother's footsteps by taking up the cause of the Halo Trust.
Guy Willoughby, Halo's chief executive, said the prince was left "irritated" and with a "bee in his bonnet" that nations are not putting in any funds to clear landmines they supplied 25 years ago.
He said the charity was "delighted" at Harry's involvement after seeing the impact of Diana's famous visit in 1997.
"The minefields that his mother visited are all now shops and roads and there's even an estate agent's on one of them," Mr Willoughby said.