Hannah Pridding and her dad Ian, from Royal Wootton Bassett, have been taking ten-mile walks along the Ridgeway in preparation for the Sahara Challenge, a sponsored 175km trek in Morocco.

Hannah, 18, a law student at the University of the West of England, and 44-year-old Mr Pridding, an IT sales manager, will walk for The Undentable Trust, a charity that helps wounded soldiers and bereaved service families.

They will have to contend with daytime heat, afternoon sandstorms and cold nights.

To sponsor them, visit www.bmycharity.com/operation sandstorm and under “Find a Friend” enter either hanscharitytrek2012 for Hannah or priddzsahara trek2012 for Ian.