Harry Shearer has reunited with the co-creators of 'This Is Spinal Tap' to sue entertainment group Vivendi for £320 million

On his former colleagues joining him in the on-going legal battle, the 'Simpson's voice actor said: "Their participation will help demonstrate the opaque and misleading conduct at the heart of this case. We're even louder now."

Guest branded Vivendi's actions "outrageous" and has vowed to challenge them until the very end.

He said: "The deliberate obfuscation by Vivendi and its subsidiaries is an outrage. It is vital that such behavior is challenged in the strongest way possible."

And McKean has called for a "reckoning" as he agrees they were not given the right amount of profits for their hard work.

He said: "'This Is Spinal Tap' was the result of four very stubborn guys working very hard to create something new under the sun. The movie's influence on the last three decades of film comedy is something we are very proud of. But the buck always stopped somewhere short of Rob, Harry, Chris and myself. It's time for a reckoning. It's only right."

While Reiner says Vivendi need to be "exposed" and made reference to a line in the movie, "up to 11", referring to the amplifier on guitarist Nigel Tufnel's guitar, but stating that he hopes the "lawsuit goes to 11".

He added: "Fair reward for artistic endeavor has long been raised by those on the wrong end of the equation.

"What makes this case so egregious is the prolonged and deliberate concealment of profit and the purposeful manipulation of revenue allocation between various Vivendi subsidiaries - to the detriment of the creative talent behind the band and film. Such anti-competitive practices need to be exposed. I am hoping this lawsuit goes to 11."

Shearer previously claimed Vivendi - who acquired the film in 1989 - reported a total merchandising income of just $81 (£66) for the 22 years between 1984 and 2006, and that total income from music sales was a mere $98 (£79).