They have scrapped their uniforms, put on black T-shirts and brought out their instruments.

The Filth, which features WA Police Commissioner Karl O’Callaghan on guitar and vocals, were one of the bands who took centre stage in the leavers’ zone yesterday.

The band consists of five members who have played for two years. They formed to play at Telethon in 2006 and then decided to formalise the band and see where it could go. They have been together ever since.

The Filth play for charity or for a “good cause only” and ‘leavers’ is one of them.

“It sends a good message to the kids that we (police) are also just normal people who have a lot of fun as well and we enjoy the music like they do,” Police Commissioner O’Callaghan said. “It helps us to connect with the kids down here, and is another way of providing good safe entertainment for school leavers.”

The Filth try to play music that people dance to so they can “get up and enjoy themselves”. They play a variety of contemporary music – “stuff that is in the hit parade now” – and some songs that are a bit older, from bands such as The Rolling Stones.

So why are they called The Filth?

Well, band member John Tuttle, who plays the base, is a former UK police officer “and in the UK criminals call police the filth”.

“The sound of the band’s name is also a reflection of the type of music that we play, which is rock,” Police Commissioner O’Callaghan said. “We prefer to play grungy rock if we can, but we don’t always, because not everybody wants to hear it, but that’s our preference.”

Since their inception, the band has gone from strength to strength and play about 15 gigs a year.

Everyone in the band is a police officer except Ross Martin, also singer and guitarist, who came in as a filler and works for Australia Post.

So what does Karl O’Callaghan listen to when he doesn’t listen to his own band?

Led Zeppelin, The Rolling Stones and The Who – all of who were big in the 70s. That should reveal how much older he is than the ones he is playing for.

“I like rock, good rock music.”