Katie was a young woman who went out with Mark Casey for a while in 1990. Kevin and Sally Webster met her when Mark brought her along on their bank holiday daytrip to Heaton Park. Not the most attentive of boyfriends, Mark described Katie to the Websters as "alright" and admitted that he didn't know her last name. At the park, Mark and Katie spent most of their time snogging.

Katie was a non-speaking part.