Conservationists on an island 28 miles off the UK mainland are concerned after signs there may be a mouse there, potentially putting a colony of seabirds at risk.

Mice and rats have been eradicated from St Agnes in the Isles of Scilly, as part of measures to protect its “nationally significant population of storm petrels”.

The Isles of Scilly Wildlife Trust said “probable” signs of a mouse including droppings and urine had been spotted, and suspects the creature was brought in within some animal feed.

The trust has been running a successful program with the RSPB and others to get rid of rodents on the islands for the past decade, which has led to the petrel population “bouncing back”, it said.