1982 and the world's loudest rock band, Spinal Tap, are about to embark on their biggest world tour to date. Along for the ride is film-maker and fan Marti DiBergi (Rob Reiner), there to make a behind-the-scenes tribute to his favourite heavy metal band. However instead of a celebrating the genius of the musicians behind such classics as "Big Bottom" and "Hell Hole", the documentary captures the cracks as they begin to appear for this band whose time has come… and now appears to have gone again. Whilst the tour turns out to be not the sell-out they had hoped for, the band's hapless manager Ian Faith (Tony Hendra) unwittingly orchestrates a cacophony of errors: stage props malfunctions, miniature sets and an all-black album cover to replace one that the record company deemed too offensive to women: "What's wrong with being sexy?" The final straw however might just prove to be the interference of guitarist David St. Hubbins's girlfriend Janine in the band's business affairs, shutting out childhood friend and co-lead guitarist Nigel Tufnel. With a camera recording all the chaos, the archetypal portrait of a band in crisis is born.

As we all know, of course, the documentary feature This is Spinal Tap was nothing of the sort but the godfather of a modern movie phenomenon known as the mockumentary, a fake documentary that plays as the real thing yet at the same time lampoons the codes and conventions of the genre it exploits. For one of its stars, Christopher Guest, it proved a career direction changer, launching him on a new career as a director of mockumentary works in the same mould such as Waiting for Guffman (1996), Best in Show (2000) and A Mighty Wind (2003).

25 years later, with Spinal Tap on tour once more, it's time to celebrate once again the much-loved and oft-quoted greatest "rockumentary" of all. Relive the band's triumphs and disasters, get your bass out for "Big Bottom" and prepare to smell the glove. With bumper extras including a ltd edition featuring a mini Marshall Amp; a brand new documentary featuring comedians and musicians celebrating 25 Years of Tap and the first Region 2 release on blu-ray, this one really promises to go up to 11...

This is Spinal Tap - Up to 11 25th Anniversary Special Edition will be released on 3-disc DVD, single disc Blu-ray disc and a rather wonderful looking 5-disc Limited Edition customised Marshall Amp (going up to 11), a fully working amp that can also be used as an iPod speaker. A fully remastered transfer will be joined by the following truckload of extras:

Disc 1:

• Brand new 25th Anniversary Documentary featuring Ricky Gervais, Eddie Izzard, Martin Freeman, Anvil, Serge Pizzorno and more (43 mins);
• Audio Commentary by the band;
• Menu commentary by the band.

Disc 2:

• The Return of Spinal Tap Royal Albert Hall concert (57 mins);
• 2007 Live Earth footage & Live Earth reunion short film (4 mins 20);
• National Geographic Stonehenge interviews with Nigel (9 mins 1)
• Sprinkle some ****in Fairy Dust On It - interview with Reg Presley of The Troggs (6 mins 54).

Disc 3:

• Outtakes (1 hr 7 mins)Original Trailers (7 mins);
• 4 x Music Videos (12 mins 27);
• TV Spots (1 min 37);
• Cutting Room Floor Deleted Scenes including Heavy Metal Memories, Flower People, Cheese Roll trailer;
• EPK featurettes (20 mins 50);
• Creative Meeting & Bitch School Videos (4 mins 33).

The Limited Edition will contain the DVD on disc 1 and will also include the original soundrack on Disc 4 and the Blu-ray edition on Disc 5.

This is Spinal Tap - Up to 11 25th Anniversary Edition will be released in the UK on 3-disc DVD (£19.99), single disc Blu-ray (£24.99) and 5-disc Marshal Amp Limited Edition (£69.99) by Optimum Home Entertainment on 7th September 2009.