Graham Roberts: "Conditions have changed dramatically"

"As otters recover, they are going to begin to move into areas where they haven't been for a long time and those conditions have changed dramatically," he said.

"We've got a lot more development pressure and with that comes the infrastructure of roads and railways.

"Now those unfortunately are very bad news for a recovering otter population."

It seems that male otters are coming off worst, the number of road casualties far outweighs the females.

This may be because male otters are the ones that seek out new territories and tend to be a bit more adventurous.

The Wildlife Trust believes well-designed fencing and otter underpasses could be the answer.

"We need things to attract otters and keep them in the water rather than encourage them to go up onto roads where they are inevitably going to get hit," Mr Roberts said.

Road users should be on the look-out for otters

Otter tunnels under one busy road near Alresford, Hampshire, have proved a huge success, and not just with otters.

"Over recent years not only has it regularly been used by otters but it's also being used by badgers as well," says Mr Roberts.

The Highways Agency has published guidelines for local authorities on how to limit the amount of wildlife fatalities.

It urges road builders to take into consideration wildlife wishing to cross the road, but still more needs to be done.

Mr Roberts says: "What we really need is for people to be aware that otters are likely to turn up more or less anywhere within the next few years.

"If you are on small roads crossing well-known water-courses be aware that otters may well be crossing that road."

But until more care is taken by road builders and road users, the otter population remains vulnerable.