Brian Clemens has died aged 83. He was a screenwriter for television series such as The Avengers, The New Avengers and The Professionals.
http://www.bbc.co.uk/news/uk-england-30775352
It was only last week that I resaw one of The Avengers episodes - The Town of No Return which was the first episode with Diana Rigg as Emma Peel - he wrote the screenplay for that episode.
RIP Brian