Graham Cole - who made his first appearance as Tony in September 1987 - will leave the long-running series later this year after producers decided that the police officer "doesn't fit" the show's "new 'dynamic'".
In an email to fan site Stampers, Cole said: "How do I tell you this? As my official website, I have to inform the 'Stampers' the management have decided that PC Tony Stamp will not be a part of the new nine o'clock show.
He continued: "I cannot tell you how disappointed and disregarded I feel. Tony has been a wonderful character to play. They say he doesn't fit the new 'dynamic' so I have to be out of the programme before the big relaunch in November. I will launch the new nine o'clock format but then they don't want any thing negative within the new show."
He added: "So poor old Tony will be sent to training school, with the door left open to come back for odd episodes."
Speaking of his exit, Cole told DS: "I have had a wonderful time patrolling the streets of Sun Hill and of course I'm sad to leave. Tony has been a big part of my life for a long time, but I'm looking forward to seeking out some new challenges and enjoying life outside the nick!"
Executive producer Jonathan Young added: "Graham is a much-loved and admired member of cast. He has contributed an enormous amount to The Bill and we are grateful for his enthusiasm and support over the years. PC Tony Stamp leaves an amazing legacy."
At the beginning of this year, it was announced that ITV's flagship police drama was to be cut to one episode per week and moved to a 9pm, post-watershed time slot.
The show's relaunch is intended to allow 'grittier and more action-packed' content.
Last week, DS revealed that The Bill will regularly air in high definition from July 1.
Cole is currently writing his autobiography, which is due to be released later this year.