TV Ratings Dec 12: Nine a Tuesday winner with help from Big Bang Theory

• Nine a Tuesday winner with help from The Big Bang Theory
• Sniffer dogs patrolling Kings Cross ends Keeping Australia Safe

The final of Keeping Australia Safe screened last night on the ABC. The series, narrated by Chris Bath and produced by ITV Studios Australia, continued its fascinating behind-the-scenes look at people keeping us safe. The final episode included some compelling footage of drug sniffer dogs working the streets around the Mediaweek office. The last night audience was 365,000.

Nine narrowly secured the biggest primary and combined channel shares. The early evening performance combined with The Big Bang Theory and then Brad and Ange in the movie Mr & Mrs Smith.

Network Ten screened the Thanksgiving Day episode of NCIS with 417,000 watching.

There was also some British royal family action last night, maybe because of the 70th wedding anniversary of the Queen and prince Philip last week.

ABC replaced Lateline with Diana: Designing A Princess with 140,000 watching.

At 7.30pm SBS screened a repeat of part one of Queen Victoria's Children to 276,000 followed by The People's Royal Wedding to 268,000.