His debut work was the audio play The Rapture for Big Finish Productions in 2002. Numerous further audio plays and prose short stories followed for Big Finish, for their Doctor Who line, spin-offs and other series (Sapphire & Steel and The Tomorrow People).
In 2005, he started working for the BBC, writing tie-in material for the new Doctor Who television series. He made his television writing debut in 2008 on the second series of Doctor Who spin-off Torchwood and subsequently wrote three two-part stories for The Sarah Jane Adventures and two two-part stories for Wizards vs Aliens. Lidster wrote for the 2014 CBBC sitcom Millie Inbetween.
Lidster writes the content for the tie-in websites relating to the fictional world of the television series, Sherlock. Alongside co-producer James Goss, he has produced Big Finish Productions' dramatic reading range of Dark Shadows audio dramas since 2011. In 2011, he script-edited the short film Cleaning Up written by Simon Guerrier and starring Mark Gatiss and Louise Jameson.
In 2012, he won the 'Audience Favourite Writer' award for his first play Nice Sally in the Off Cut Theatre Festival.
From 2005 onwards, he wrote the fictional content for the Doctor Who tie-in websites including the MySpace blog for Martha Jones. In 2007, he edited the Doctor Who short story collection Short Trips: Snapshots. The following year, he wrote "Mad Martha" for the Doctor Who website. In 2007 and 2008 he abridged a number of Doctor Who and Torchwood novels for BBC Audiobooks, including Sting of the Zygons, Wooden Heart, Another Life, Border Princes and Slow Decay. He also wrote the fictional blogs of Sherlock Holmes, John Watson, Molly Hooper and Connie Prince, as part of the BBC Sherlock series.
- "Sherlock:Other Sherlock related websites". BBC Online. Retrieved 25 July 2010.
- "Cleaning Up". Retrieved 6 August 2013.
- "Off Cut Festival". Off Cut Festival. 13 October 2012.
- "the plays – Off Cut". Retrieved 14 September 2012.
- "Skylight Theatre". Retrieved 30 October 2013.
- "The Collective Project 2013". Retrieved 25 November 2013.
- "Shorts New Writing". Retrieved 3 June 2014.
- "42: Prologue". BBC. 2007.
- "Doctor Who Adventure Calendar". BBC. 2012.
- "Voices from the Past". H&H Books. 2011.
- "Shenanigans". Obverse Books. 2013.
- "Mad Martha". Joseph Lidster. 2008.
- Disclaimer on the BBC1 Official website http://www.bbc.co.uk/programmes/b018ttws/features/disclaimer