Conservative Councillor Mike Bawden has announced that he will not be seeking re-election to the Borough Council on May 22 - after nearly half a century serving the town.
Councillor Bawden (Chiseldon and Lawn) is standing down for health reasons after being diagnosed with luekaemia last month.
Councillor Bawden said: “It has been an honour and a privilege to represent so many residents of this Borough since I was first elected to Swindon Borough Council in 1967.
"Over that time, Swindon has changed almost beyond recognition with thousands of new homes and new industries. Where there were fields to the east, west, and north, there are now homes and places to work.
"While the prognosis for my leukaemia is very good, I will not be able to assume the rigours of either ward work or an election campaign. Since I cannot give my constituents the 100% commitment they deserve, I have, with sadness, decided to step away.
"I would like to thank all my colleagues and officers, with whom I have worked over the years.”
Councillor David Renard, Leader of the Council added: “I would like to praise Mike for his four decades of public service to this town, including two terms both as Mayor and as Leader of the Council. I will miss his knowledge, experience, tenacity, and advice.
"Outside his political work, Mike set up the annual Marriott Charity Ball and Swindon Cares. He played a key role in the Great Ormond Street appeal in Swindon in the late 1980s.
"Some people will have forgotten that in 2003, Mike took over a minority administration running a council that, under his predecessors had been rated one of the worst in the whole country.
"By 2006, when he stood down as Leader, Swindon was well on the way to recovery. Without the tough but necessary decisions he took then, we would not be the efficient, effective, and economical council that we are today.”