'Eco-debt' Britain will have consumed this year's share of resources by tonight

At about bedtime today, Britain will go into ecological debt - the moment when the country begins living beyond its natural resources and eating into nature's 'capital'.

Research by the New Economics Foundation think-tank shows that in the early Sixties it took Britain more than half the year before it went into 'eco-debt' on 9 July; by last year the date had moved to mid-morning on 16 April and this year it is 12 hours earlier still - 10.42pm on 15 April. The world as a whole is expected to go into eco-debt in late October.

Consumption beyond the globe's natural resources is reducing the ability of the planet to provide clean water and food and absorb the pollution blamed for climate change, said Andrew Simms, the report's author.

'The irony is, while our consumption has gone up, levels of satisfaction have flat-lined. So we're doing all this - putting the prospect of lifting people in developing countries out of poverty at risk and putting the eco-system at risk - for no really good reason.'

Sustainability consultants Best Foot Forward calculated the resources used to produce everything Britons do and buy, from air travel to avocado salad, using UN trade figures and other international statistics.

Eco-debt calculations use 'rules of thumb', and this year's estimates are based on data from 2003, raising a question mark over the exactness of timing. But the broad message is clear: crowded affluent countries such as Britain, the Netherlands and Japan go into eco-debt much earlier.

The United States and Australia, though also rich, follow weeks later because they have such huge resources. China and India go into eco-debt about the same time as the US because of their huge populations.

About two-thirds of the impact of all consumption is the pollution caused by energy use; other major factors include factory fishing and global deforestation, said Simms.

'Like a savings account, the planet produces so much natural interest every year, and what we have to be doing if we were living sustainably is living off the interest; what we are doing is eating into the capital,' said Paul King of WWF (formerly the World Wildlife Fund), which has calculated that, if other countries adopted British lifestyles, humans would need three planets to allow them to live sustainably.

A 'calculator' for organisations to measure their environmental footprint is being developed by Best Foot Forward. See Footprinter.com