Ecuador's congress authorised drilling for oil in the Yasuni national park on Thursday night.

After 10 hours of debate, MPs approved President Rafael Correa's plan by 108-25.

The decision was a major setback to environmentalists who had earlier hailed Mr Correa's push to avoid drilling in the Amazon rainforest.

He had sought more than £2.2 billion in donations - half the expected oil revenue - from other countries to maintain a moratorium on drilling in the national park.

Green campaigners lauded the 2007 initiative, saying it set an precedent in the fight against global warming by easing the massive burden it placed on developing nations.

But those hopes were dashed in August when the president said he had been forced to abandon the plans because just £8 million had been raised, adding that wealthy countries had "failed" Ecuador.

The oil lying under the Yasuni is thought to account for roughly 20 per cent of Ecuador's reserves.

The congress decision did place conditions on drilling aimed at minimising the impact on the environment and local tribes and Mr Correa said more than £12bn of the projected earnings would be put towards battling poverty.

But that's unlikely to placate the thousands who have signed petitions demanding a referendum on any oil extraction in the Yasuni.

More than 100 scientists wrote a join letter to congress ahead of the vote warning that the development would damage a site of special biodiversity.