Williams has made major impact since joining in the summer

Williams, 35, only joined the club in the summer from Coventry but has made a huge impact as skipper.

He steps into the gap left by Dennis Wise who has taken over at Leeds, with his assistant Gus Poyet.

Dave Tuttle initially accepted the post before changing his mind, saying: "I have given it a lot of thought and decided it's not right."

Despite turning down the caretaker role, Tuttle insists he wants to stay at the club.

"I am committed to Swindon and want to continue developing my current role with the youth team and scouting," he added.

Swindon's acting chief executive Martyn Stames said Tuttle had the "full backing of everyone at the club".