ALIEN life forms will be the theme of this year's prestigious lecture in memory of a nature lover.

Doctor Phil Gates, a writer and lecturer at Durham University, will deliver a lecture entitled Alien Species - Encourage or Eradicate, as part of the Elgee series of talks.

He will discuss the problem of the colonisation of the British environment by plant life from other countries and any prevention measures that we should take. Dr Gates is a regular contributor to BBC wildlife programmes.

The Elgee Lecture, which is sponsored this year by the Cleveland Naturalist's Field Club, was founded in memory of Frank Elgee, a keen naturalist and curator of the Dorman Museum from 1904 to 1932. It takes place at the Leeds University Centre, on Harrow Road, Middlesbrough, at 7.15pm tomorrow