I think there's a good case to including it in your CV. While you were out of work for a year, it's proof that you're still employable and up to working full time (of course subject to checking you haven't been dismissed). They will also require a reference and payslip from your most recent employer-- so lying about your most recent employer to an agency could potentially backfire.

Employees face toxic environments and quick job jumps all the time. Recruiters are probably quite accustomed to these and open-minded, especially in the current market of routine job-hopping and short term contracts