A mother whose son went missing in Africa six months ago has spoken of her heartbreak.

Pauline Velten said the whole family was "desperately worried" about Christian, who disappeared in March on a 4,000km trek across west Africa.

He was following in the footsteps of 18th Century explorer Mungo Park, along the River Niger, from Mali, through Niger and Nigeria. He hoped to make a documentary of his travels.

Mrs Velten said she, her husband Timothy and their daughter Hannah last heard from Christian when he was in Kita in Mali on March 23.

Since then, Mrs Velten has contacted the Foreign Office and British embassies and Interpol have also been informed.

But nobody has heard anything from Christian, who lives in Brighton.

Mrs Velten, from Burwash, near Heathfield, said: "I have to believe my son is still alive or I wouldn't be able to carry on. The not knowing is tortuous. Is he sick with malaria or typhus but alive in a village somewhere being looked after? Has he drowned or has he been kidnapped?

"There are crocodiles, lions and hyenas. As he was on his own in a tent in the wilderness, anything could have happened. Every night in bed I go over and over all the possibilities.

"During the day I'm on the phone, trying to make things happen.

"Whatever happens, we have to find him - even if what we find is what we are dreading the most."

Mrs Velten said Christian, 28, had always been adventurous and she thought he had nine lives.

However, concern mounted when the family heard nothing from him for weeks and then months.

She said: "His idea was to make a documentary showing how west Africa has changed over the past 200 years and he managed to convince a production company to lend him a video camera.

"He spent six months researching the trip. He planned to start in Gambia, then go through Senegal and on to Mali from where he planned to follow the Niger to the coast.

"He was concerned about going through Nigeria because there had been reports of bandit attacks. But he liked travelling on his own so he took the risk and I think he gets a buzz surviving hardship."

Christian was due to fly home on July 22 and when he did not make the flight, panic started setting in.

Mrs Velten said: "The police in Mali said they would begin a search on August 30. I was in a dreadful state - I didn't know if my son was alive or dead and nobody could give me any information.

"Communication between us, the Foreign Office and the police in Mali was terrible.

"More than a week later they told me the two policemen who had been allocated to us were still searching.

"We considered this good news because it meant they hadn't found a body.

"But a few days later the Foreign Office told me the search had never begun - we had been misled. I was so upset I just collapsed in tears."

Mrs Velten said Interpol was now involved and a search was being planned. However, the cost for the hunt would cost thousands of pounds.

Anyone wishing to contribute to the search fund should email search@technicola.com or visit www.technicola.com/chris