Standing almost 6ft tall, with six inch claws and a top speed of 40 miles an hour, it does not sound like it would blend in well in the Fenland countryside.

Eastern Daily Press: The rhea is a large bird native to South America, related to the ostrich and emu.The rhea is a large bird native to South America, related to the ostrich and emu. (Image: Archant)

Yet a rhea – a flightless ostrich-like bird native to South America – is currently on the loose in Britain's flattest landscape.

The authorities have not yet established how the creature came to be roaming the area, but it has, thus far, evaded attempts to capture it.

The bird has been spotted several times in recent weeks, with the most recent sighting near the A17 at Terrington St Clement yesterday morning.

Officers were dispatched to the scene, but their search proved fruitless.

Several rheas are now kept as pets in the UK and police are working with the RSPCA in a bid to track down the Fens fugitive's owner so it can be coaxed back home.

Sharon Stockdale, receptionist at Terrington Veterinary Centre, said one of her colleagues living on Lynn Road spotted the rhea in her back garden earlier in the week.

'I heard lots of people were chasing it. You would think if you drove down the A17 you wouldn't miss it.'

But her colleague, Sharon Place, added: 'You wouldn't catch one of those in a hurry.'

Ian Collison, one of the owners of J.A. Collison & Sons farm in Terrington, said he had spotted the rhea when shooting in late December at Tilney St Lawrence, near the A47.

'It was about 50 yards away in the game cover and as the beaters walked up to the cover it ran away. As they walked up they spooked it.'

According to some reports in the area, the renegade has been in the region for several months, apparently living happily.

However, the net may now be tightening around it.

The RSPCA have asked for any sightings to be reported to them or the police and urged members of the public not to approach it.

A spokesman said the birds were potentially dangerous as they were strong, fast and had sharp claws.

For now, though, the fens fugitive remains at large.

If anyone does spot the rhea they can contact the RSPCA on 0300 1234 999.