"On the Inside" is the theme song for the Australian soap opera Prisoner (known as Prisoner: Cell Block H in some territories). It was written by Allan Caswell and performed by Lynne Hamilton.

Caswell recalls that his 'publisher was having lunch with a guy from Grundy's one Friday and asked what they had coming up. They already had music for Prisoner, but the final decision was being made on the Monday and if we could get something to them by then they'd listen to it. ""I didn't get a chance to work on it until the Sunday afternoon. It was like buying a lottery ticket _ either I write something and it might get accepted or I don't write something and not give myself a chance." Caswell recorded the song on a portable cassette player 'and gave it to his publisher who delivered it without listening to it. "Within five days, I was in the studio with Lynne Hamilton. She got half way through the song and burst into tears. Anyone who believed in it like that was going to do a good version of it."'

The song was a hit in Australia in 1979 when the television show was launched, and reached number three in the UK singles charts in 1989 when the show attracted millions of viewers in its late night slot in ITV regions.

In 2009, writer Allan Caswell alleged that Alabama's song Christmas in Dixie was 'ripped off' from "On the Inside", but conceded that legal action was unlikely as both he and Alabama were signed to Sony.

The song was rerecorded and released by singer Ella Hooper to coincide with Foxtel's Australian re-run of the series, which started in March 2011.Reggae singer Donna Marie has also recorded a version, with minor alterations to some lines.

Although the song was not used as the theme for Wentworth, the 2013 reimagining of Prisoner, it was briefly heard in the pilot episode, being hummed by Jacs Holt (played by Kris McQuade), the show's main antagonist.

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