Jemma Redgrave, Ingrid Oliver and David Tennant are among those who've appeared in Big Finish's UNIT stories since they started in 2004. Until mid-day on Monday (UK time) you have a chance to make the most of special offer prices across all of them...

UNIT - The Coup, starring Nicholas Courtney and Siri O'Neal, has been one of the hits of the Big Finish For Free range - download it today for absolutely nothing! Nicholas's reading of his memoirs, A Soldier in Time, is available on download for £8.99.

The four UNIT stories from 2004-2005 can be bought individually for £2.99 on Download or £4.00 on CD or in a UNIT Series 1 bundle at £10 and £15 respectively.

In 2012, UNIT encountered a Doctor... or two! in the epic boxed set UNIT - Dominion, starring Sylvester McCoy, Alex Macqueen, Sophie Aldred and Tracey Childs. This is currently half price on CD at £20, and less than half price on Download at £15.00.

In November 2015, Big Finish were proud to release the first of UNIT - The New Series. In UNIT - Extinction, Kate Stewart (Jemma Redgrave) and her team including Osgood (Ingrid Oliver), Sam Bishop (Warren Brown) and Captain Josh Carter (James Joyce) confronted a new Nestene Consciousness attack on Earth and then the Tengobushi in UNIT - Shutdown. Both of these four-episode titles are currently £20 on Download, and £22 on CD.

For some reason, a few of our Listeners forgot that UNIT encountered The Silence in November for UNIT - Silenced, which has been getting rave reviews since release and is still at its frozen pre-release price of £20 on CD or Download.

In May next year, Kate's team meet both friends and foes from the past, when Yates (Richard Franklin), Benton (John Levene) and Jo (Katy Manning) come out of retirement to help against Silurians and Sea Devils in UNIT - Assembled. This can be pre-ordered today for £20 in either format.

All four of the UNIT - New Series series are available through Big Finish Bargain bundles at £80 for either format. Bundles collecting just UNIT - Shutdown, UNIT - Silenced and UNIT - Assembled are currently available for £60 each. All CD purchases unlock a download version - if you're using the free Big Finish app for iOS or Android, you can be listening within minutes!