A determined mother says she might have to sell her home to fund her son's expedition along the Amazon.

Ba Stafford's son, Ed, is more than 500 days into his Amazonian adventure trekking the length of the world's longest river to raise money for charity.

He needs £2,000 a month to pay for guides, food and accommodation.

But the pot ran dry after his main sponsor, international recruitment firm JBS Associates, pulled out for financial reasons, blaming the credit crunch.

Now Ba, 65, from Mowsley, near Lutterworth, says she will do everything she can to keep her son's expedition alive – including putting her £300,000 home up for sale if new sponsors do not come forward.

She said: "I am very much hoping not to have to sell my house.

"But there's no way I'm going to allow him to fail just because he hasn't got any money.

"Everybody says I'm crazy for thinking about putting it up for sale, but he's doing such an amazing task – it's something that's never been done before.

"It's at least as difficult as climbing Everest and to pull out now would be a tragedy."

Ed, 33, is walking 4,000 miles along the Amazon river in South America from its source in Peru to the river mouth in Brazil.

He will become the first person to do the journey on foot when he completes the trek, which is expected to be in May 2010.

Despite being short of funds and unable to buy food or shelter, Ed and guide Gadiel "Cho" Sanchez, who has joined him, continue to fight their way through the jungle.

Ed said: "Cho and I have no option but to see this as part of the adventure.

"There seems no point in feeling sorry for ourselves – but just we need to ensure we have enough food to eat. We will be permanently based from our hammocks for the foreseeable future and relying far more on fishing and foraging to stay healthy."

He hopes to raise more than £100,000 for charity, including £20,000 for Cancer Research UK, by doing the trek.

Spokeswoman for the cancer charity Paula Young said: "It's amazing the lengths some of our fund-raisers will go to but Ed has really pushed the boundaries of physical and mental strength to get this far. Cancer Research UK relies entirely on voluntary donations to fund its work so we are extremely grateful to Ed and wish him all the best in on his unbelievable adventure."

The rest of the money will be split equally between the Rainforest Concern, The ABC Trust (Action for Brazil's Children), Project Peru and The ME Association.