Siobhan Mailey is a well-off, good-looking girl who initially looks down her nose at Waterloo Road. Siobhan's no pushover, but is impressionable when it comes to the iron will of best friend Amy, and she quickly becomes embroiled in the girl gangs, doing things she'll learn to regret.
Essentially, Siobhan just wants to fit in but when she tries to leave her gang, life gets tough. The girl gang also puts a strain on her relationship with boyfriend Luke – if her mates all think the Waterloo Road pupils are scuzzers, then what must they say about him?
It is made clear in the last half of series 5 that her and boyfriend Luke have split up off the screen and he is not at Waterloo Road anymore.
She is interested in Finn at the start but not as much as Amy is. He kisses her on the farm trip but Amy sees, gets jealous and squashes and egg on her head this starts a massive egg fight and causes Josh to be taken to hospital. Siobhan agrees not to go anywhere near Finn but Amy starts a relationship with him and it is obvious Siobhan is being ignored. She gets closer to Sambuca Kelly and Lauren Andrews and at the Prom she is seen dancing with Lauren. by the end of season 5 she moved schools