A 250-mile (400 km) fundraising desert trek by wounded ex-service personnel has been launched by Prince Harry. The Walk of Oman will see a team tow a provisions cart weighing 660lb (300kg) across the dunes of the Empty Quarter. The Duke of Sussex has been a patron of organising charity Walking with the Wounded since it was founded in 2010. He accompanied previous walks to the North and South Poles and in the UK but it is not yet known if he will join the three-week trek in November. The charity supports former members of the British armed forces to regain independence through employment.