Most famous for his more than decade-long performance as Arthur Fowler on the BBC's EastEnders, Treacher also contributed to such film and radio productions as, respectively, Tale of the Mummy and Bringing Eddie Home.
After training at London's Webber Douglas Academy of Dramatic Art, he began his London West End stage career in a production of Shout for Life.
In the early 2000s, he guest-starred in episodes of Casualty and The Bill.
His marriage to Australian television actress Katherine Kessey resulted in children named Sophie and Jamie.
He played the father of Susan Tully's EastEnders character.