CABINET member Peter Mallinson has lost his seat.
He was beaten by Ellen Osa, who also becomes Swindon's first black female councillor.
She scooped 1,063 votes compared to the tory's 768.
The new Coun Osa said: "It's brilliant. It's history in the making.
"To be the first black woman councillor in Swindon is just unbelievable."
Mr Mallinson was one of only two Conservative councillors not to be re-elected.
For the results of all the candidates, see our Election 2011 section.
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