We're introduced to Jill (Lydia West) in the first episode, as she spots Ritchie peeking into her drama class. They immediately become friends, and she and Ritchie meet up on a night out, where she introduces him to the rest of the friend group. They all end up living together in the Pink Palace, and rumours of a disease, which eventually becomes HIV and AIDS, begin to spread.
After Gregory asks Jill for help and she witnesses him being taken home, she becomes concerned and worried for the other boys. She's seen by Colin's side before he passes, and she aims to do the same for Ritchie — but his mother won't allow it.
In the end, having lost a number of her closest friends, Jill ends up volunteering at hospitals to spend time with AIDS patients. According to Russell T Davies, West's character was based on his real-life friend Jill, who "spent time on AIDS' wards" and "held the hand of the dying." Jill was such an inspiration on Davies's life that "I couldn't even change her name when it came to writing a fictional version," he told Channel 4.
Image Source: Channel 4