Britain's oldest tree appears to be undergoing a sex change.

The Fortingall Yew in Perthshire, which estimates suggest is between 3,000 and 5,000 years old, is regarded as a male tree because of the fact it produces pollen – unlike female yews, which produce distinctive seed-bearing red berries.

But botanists have spoken of their surprise after finding three red berries on a branch of the yew this year - in signs at least part of the male tree is becoming female.