Joss Whedon's superhero epic recorded the third-biggest Thursday opening of all time in the territory, behind Harry Potter and the Order of the Phoenix and first-placed Star Wars: Episode III - Revenge of the Sith.
The news follows reports that Avengers has broken launch day records in New Zealand and Taiwan, as well as turning in impressive takings in Australia and France.
Bolstered by positive reviews in the press, Avengers has been given additional screenings at cinemas across the UK to cater for the demand.
The film, titled Marvel Avengers Assemble in the UK, has been tipped to gross more than $150 million (£92.7m) when it lands in the US on May 4.
Avengers debuted in UK theatres yesterday (April 26).
> 'The Avengers' London press conference - video in full
> 'The Avengers' preview: 10 teasers for Marvel's superhero epic
Watch a trailer for The Avengers below: