The large mature oak at the rear of Whitecliffe Surgery, Blandford, Dorset, has been infected by two aggressive decay fungi - fistulina and inonotus.

A consultant said the inonotus is "particularly worrying" as it is decaying the roots, making it unstable.

"It is a terrible shame it is being removed," said Jeremy Partridge, of North Dorset District Council.

"This is a magnificent tree which is probably very old, possibly 300 years.

"We will ensure that a replacement is planted."