Oak tree rings used to track 800-year-old climate

Rings inside oak trees have always told us their age.

Now scientists are using them to study the weather in medieval times.

Studying the rings has allowed them to produce one of the most detailed records yet of how the UK's climate has changed over the last millennium.

It reveals a picture of summer rainfall stretching back more than 800 years, according to Mary Gagen from Swansea University.