Platt was able to do this as his month-to-month deal expired at midnight last night, allowing him to immediatly jump ship.
Platt told Posh's official website: "It is great that my future has been secured because it was difficult on a monthly contract. The deal at County was changed a bit and when I heard Barry was interested, I was keen to sign and sort my future out. When I joined Notts from Rochdale, Billy Dearden and Steve Parkin had just joined and things were looking up for the club, but things haven't really worked out and Billy left Meadow Lane after the game on Tuesday night."
Platt added: "Obviously, Posh are just outside the relegation zone, but it was a good win over County and there is a little cushoin ahead of the back four."
Platt was also rumoured to be attracting interest from QPR, Sheffield Wednesday and Barnsley. Oh, and Steve Jenkins recommended Peterborough to him, how nice.
More on this amazing days events still to come on NCM.