Friends and relatives of a zoologist lost in Africa could approach survival expert Ray Mears for advice.

Christian Velten, 28, was last heard from in March shortly before he set out to follow the River Niger.

His route was to take him through Mali, Niger and Nigeria but he did not arrive home last month as planned.

Christian was living in Brighton before his departure and his parents Pauline and Timothy live in Burwash, near Mr Mears' home.

Mr Mears founded a programme called Woodlore to teach people survival skills and has presented a number of popular television programmes, including World Of Survival and Extreme Survival.

Christian's friend, Alex Bird, of Regency Square, Brighton, said: "Chris had been to Africa before a few times but not specifically to those parts.

"We don't know what has happened but we have got our fingers crossed. Ray Mears apparently lives near Chris's family in Sussex so we may be able to get some advice from him."

Interpol are hunting for Christian but friends and family are wondering if they should send someone else out to Africa in a bid to track him down.

Alex said Christian set off with a camera and a few thousand pounds in cash in February.

He said his friend was used to roughing it after spending a year researching flora and fauna in the Caribbean bush.

He was hoping to publish a book of his adventures following a route taken by the 18th Century Scottish explorer Mungo Park.

The Foreign Office's travel advice to the region states the "vast majority" of visits are trouble-free, providing sensible precautions are taken.

However, British citizens are warned against travel near the Mali-Niger border because of bandits.