Director Michael Bay's 3D robot blockbuster, starring Shia LaBeouf and Rosie Huntington-Whiteley, pulls in £10.7 million in ticket sales after opening in Brit cinemas last Wednesday.
Dark of the Moon's opening surpasses the debut for Transformers in 2007 (£8.7 million) and its 2009 sequel Transformers: Revenge of the Fallen (£8.4 million).
Last week's chart leader Bridesmaids slips to number two, but still maintains a healthy second-week gross of £2 million. Kung Fu Panda 2, Bad Teacher and new release Larry Crowne - starring Tom Hanks and Julia Roberts - complete the top five.
Elsewhere, controversial Bollywood movie Delhi Belly opens at number nine with £155,000.
The UK box office top ten in full:
1. (-) Transformers: Dark of the Moon - £10,728,503
2. (1) Bridesmaids - £2,007,171
3. (2) Kung Fu Panda 2 - £728,598
4. (4) Bad Teacher - £512,069
5. (-) Larry Crowne - £346,486
6. (5) The Hangover Part II - £301,482
7. (3) Green Lantern - £279,485
8. (6) X-Men: First Class - £215,011
9. (-) Delhi Belly - £155,211
10. (7) Pirates of the Caribbean: On Stranger Tides - £148,362
Watch Digital Spy's interviews with Transformers star Rosie Huntington-Whiteley and director Michael Bay below:
Watch the trailer for Transformers: Dark of the Moon below: