It may be deemed the British film most likely to register at the Oscars and BAFTAs, but UK box-office sleeper “Tinker, Tailor, Soldier, Spy” had to take a back seat to the little guys at tonight’s British Independent Film Awards in London. Instead, it was Paddy Considine’s hard-hitting directorial debut “Tyrannosaur” that surprisingly emerged as the night’s big winner, taking three awards including Best British Independent Film.

Considine’s debut is a vastly impressive and assured one, striking its emotional notes hard and serving as a vehicle for some startling performances — the most haunting of which, Olivia Colman’s grievously abused middle-class samaritan, was a richly deserving winner of the Best Actress award. (Tilda Swinton’s run of luck this week, which saw her triumph at the National Board of Review and the European Film Awards, came to an end here.)

I’m not convinced that “Tyrannosaur” quite merits the top prize ahead of more formally ambitious works like “Shame” and “We Need to Talk About Kevin,” but I commend the BIFA jury for placing their chips on a film so brutal and uncompromisingly bleak, and the least commercially successful of the nominees. Last year, “The King’s Speech” swept the board here, prompting many to accuse the BIFAs of selling out on their independent principles; one wonders if that factored into their decision this year.

Still, “Tyrannosaur” was far from a sweeper, as the BIFA jury found a way to recognize most of the major players on the nominee list. Though Swinton missed, “We Need to Talk About Kevin” was rewarded with the Best Director prize for an absent (on honeymoon) Lynne Ramsay — a nice bookend to the Best Debut Director award the Scot won 12 years ago for “Ratcatcher.” (This year, that prize went, logically enough, to Considine too.)  

Michael Fassbender’s Best Actor award for “Shame” was as inevitable as it was deserved; more surprising was the Best Supporting Actor honor for Irish character actor Michael Smiley for the gutsy quasi-horror film “Kill List.” Perhaps he benefited from the difficulty inherent in choosing between “Tinker, Tailor” stars Tom Hardy and Benedict Cumberbatch, though it was also an apt way to reward a significant critical hit whose violence could possibly have polarized the jury.

Over in Best Supporting Actress, Oscar frontrunner Vanessa Redgrave scooped her first trophy of the season for her towering performance as Volumnia in Ralph Fiennes’s revisionist Shakespeare adaptation “Coriolanus”; it will surely not be her last. The only other such race-leader to snag a prize tonight was “A Separation,” which predictably took Best Foreign Film. (Nothing wrong with predictability in this case.) One would like to say the same about “Senna,” a no-brainer winner for Best Documentary (not least since it was also nominated for Best Film), but we all know how that turned out.

In an evening full of well-earned victories, the most heartening for me personally was the brace of awards won by Andrew Haigh’s exquisitely low-key gay romance “Weekend.” Sadly under-nominated in the first place, the surprise arthouse hit won both awards it was up for: Most Promising Newcomer for co-lead actor Tom Cullen, and Best Achievement in Production. (I’m not sure how one blindly judges production, but given that Haigh’s film was made on an astonishing budget of £120,000, I have no doubt it’s a worthy winner.)

Indeed, the only film that likely comes away tonight feeling a little miffed is, well, “Tinker, Tailor, Soldier, Spy”: from seven nominations, the film took only the Technical Achievement Award for Maria Djurkovic’s extraordinary production design. (Please take note, Academy.) It’ll have its day, quite possibly, at the BAFTAs; I suspect that might have been the jury’s reasoning too.

All in all, a fine set of winners representing a pretty remarkable year for British cinema. The ceremony itself, meanwhile, was an entertainingly scrappy affair — thanks mostly to host Chris O’Dowd, newly of “Bridesmaids” fame, who spent the evening getting so paralytically drunk as to make the Golden Globes look positively funereal. Staggering about on stage, calling Vanessa Redgrave a “sexy owl,” and doggedly maintaining an off-the-wall running joke about presenter Ron Howard sexually harrassing Carey Mulligan, he’s unlikely to threaten Billy Crystal’s position any time soon, but he sure was fun to watch.

Full list of winners: 

Best Film: “Tyrannosaur”

Best Director: Lynne Ramsay, “We Need to Talk About Kevin”

Best Actress: Olivia Colman, “Tyrannosaur”

Best Actor: Michael Fassbender, “Shame”

Best Supporting Actress: Vanessa Redgrave, “Coriolanus”

Best Supporting Actor: Michael Smiley, “Kill List”

Best Screenplay: Richard Ayoade, “Submarine”

Best Foreign Film: “A Separation” 

Best Documentary: “Senna”

Best Debut Director: Paddy Considine, “Tyrannosaur”

Most Promising Newcomer: Tom Cullen, “Weekend”

Best Achievement in Production: “Weekend”

Technical Prize: Maria Djurkovic (production design), “Tinker, Tailor, Soldier, Spy” 

Richard Harris Award: Ralph Fiennes

Best Short Film: “Chalk”

Raindance Award: “Leaving Baghdad”