Knightley plays Elizabeth Bennett in Pride and Prejudice

Highly-praised graphic novel adaptation A History of Violence opened at number two, with soccer film Goal in at three.

Guy Ritchie's much-maligned movie Revolver dropped six places to eighth overall, taking 59% less in ticket sales than in its debut week.

Pride and Prejudice, which also stars Matthew Macfadyen, has now taken almost �10m at the box office in three weeks.

There were only two other new films in the top 10 - crime drama Four Brothers, starring Mark Wahlberg, entered the chart in fourth spot while comedy Deuce Bigalow: European Gigolo took ninth position.

A History of Violence is being tipped by some critics for Oscar success next year.

Directed by David Cronenberg and starring Viggo Mortensen, it tells the tale of a family man whose past catches up with him.