Purse joins Valiants
The 35 year-old has signed a deal until the end of the season after leaving Plymouth.
He has previously had spells at Birmingham City, West Brom, Cardiff and Sheffield Wednesday and played more than 450 league games.
Boss Micky Adams (pictured) said: "He is vastly experienced, he knows the job, he's a leader and he is vocal, so that's the sort of quality that we need, hopefully to take us forward.
"We have signed Chris Birchall as well and we have got other irons in the fire.
"We are talking to Liam Chilvers and his agent and hopefully we can tie him up."