The top ten comedies of all time...

Still from the 1984 mockumentary 'This Is Spinal Tap' which has been rated the greatest comedy of all time. Photo / supplied

Spoof music documentary This Is Spinal Tap has been ranked the greatest comedy movie of all time by experts.

The 1984 film, featuring a cast of unknowns who made much of it up on the spot, triumphed in a poll for Time Out magazine ahead of Airplane! and Life Of Brian.

A panel of comedy stars including Dan Aykroyd, Jackie Mason, Stephen Merchant and Jack Whitehall compiled the top 100.

Mockumentary Spinal Tap was released to little fanfare while some viewers were convinced the group - which had a knack of losing drummers in freak accidents - were a genuine band.

Word of mouth about the film, which parodied bands such as Status Quo, Led Zeppelin and Black Sabbath, helped it to become a sleeper hit.

To master their characters the band played several shows, even supporting heavy metal band Iron Butterfly. And ironically, some Tap songs were later adopted by other bands - the hard rock act Soundgarden would regularly perform the track Big Bottom.

The film's deadpan lines - such as "It's such a fine line between stupid and clever" and "What's wrong with being sexy" - have had an enduring appeal.

"It's sublimely funny and sharp - a comedy built for the long haul which matures with each viewing. It's so perfectly constructed and performed, the characters so rich and realistic, that it's initially a challenge to determine the dividing line between reality and fiction," Time Out film critic David Jenkins said.

THE TOP TEN COMEDIES IN THE TIME OUT LIST ARE:

1. This Is Spinal Tap (1984)

2. Airplane! (1980)

3. Monty Python's Life of Brian (1979)

4. Annie Hall (1977)

5. Monty Python And The Holy Grail (1975)

6. Anchorman: The Legend Of Ron Burgundy (2004)

7. Withnail And I (1987)

8. Groundhog Day (1993)

9. Some Like It Hot (1959)

10. The Jerk (1979)