Optimum’s horror The Last Exorcism debuted top in the UK over the Sept 3-5 weekend, giving the distributor its biggest ever three-day opening.

Daniel Stamm’s feature took $1.7m (£1.1m) from 313 screens for a screen average of $4,436 (£3,530). The number-one opening is Optimum’s first ever at the UK box office and represents a significant landmark for the indie, which could well achieve its second chart topper later this year after parent company Studio Canal this week announced a December UK release for Florian Henckel Von Donnersmarck’s The Tourist, starring Johnny Depp and Angelina Jolie.

It has been a good week all round for Optimum as Four Lions entered the UK DVD market as the highest new entry this week after selling 34,125 units.

The Last Exorcism is also the first horror to debut at number one in the UK since The Final Destination one year ago.

Paramount’s comedy Dinner For Schmucks opened in second place, taking $1.4m (£940,586) from 428 screens at an average of $3,385 (£2,198) and LionsGate’s comedy-drama The Switch opened in sixth position grossing $1m (£666,018) from 357 screens for an average of $2,873 (£1,866). Unsurprisingly, ever reliable Toy Story 3 saw the smallest change in fortunes of all top 20 films, posting a -38% weekend change.

While The Last Exorcism represents a landmark for Optimum, the $1.7m (£1.1m) total is the second lowest number one debut at the UK box office since The House Bunny grossed $1.4m (£894,188) in October 2008 (the lowest being June’s Killers, which only managed $1.5m (£1m), and spells trouble for the September box office. While last weekend’s total box office is stronger in depth than the disastrous last weeks of June, September 2010 could well follow September 2009 as the worst performing month of the year.

September is historically a very weak month in the UK, as the largest proportion of regular cinema-goers re-focus their attentions on school or work, and because the major distributors have usually played their trump cards over the summer and wait until nearer Christmas to unleash the next blockbusters. 

The biggest chances of September splashes look to come from the three Sony titles Resident Evil: Afterlife, The Other Guys and Eat Pray Love, and from Momentum’s Tamara Drewe.

Indeed, we’ll know more after this weekend coming as the aforementioned Resident Evil and Tamara Drewe hit UK screens, alongside Fox’s comedy Cyrus and eOne’s drama The Runaways.