Earthworms could die out if urgent action is not taken, experts have warned.

Recent data suggests that the UK's earthworm population has decreased by a third over the past 25 years.

This decline is likely to have agricultural impacts, such as soil quality and crop yields. It could also spell disaster for thrushes, wading birds and small mammals that rely on earthworms for food.

In a study published last year in the journal PLOS One, it was reported that earthworm populations could be declining by up to 2.1 per cent annually. 

Despite these findings, no new nationwide studies have been commissioned to further investigate the situation, according to Jackie Stroud, a soil scientist at the University of Warwick.

'In England, little is known about the state of soil because it has not been included in environmental policies for decades,' she told The Times.

'[We need] a change in policy to really invest in looking at this, looking at the latest soil science to monitor earthworm populations so we have data-driven decisions.'

James Pearce-Higgins, a zoologist at Cambridge University and director at the British Trust for Ornithology who co-authored the paper on earthworms, called the findings 'hugely concerning' because of the essential role earthworms play in ecosystems. 

'They're responsible for nutrient cycling, for aerating the soils,' he said. 

'And they're important food. We see declines in some of our thrushes and waders that feed on earthworms... It does seem to be the case on farmland and also, slightly to our surprise, in woodland.'

He added that new studies were needed 'really, really urgently'.

And Mark Hodson, a soil expert based at the University of York, said: 'Plants grow up to 30 per cent better in the presence of earthworms.'