Paul O’Grady: For the Love of Dogs, STV, 8pm

The canine-loving comedian is back for a new run of the acclaimed documentary set in Battersea Dogs and Cats Home. Episode one features a dachshund and her pups, which staff suspect have escaped from a puppy farm. She’s made a new home on a golf course, so the employees name her Birdie. Because two of the puppies have eye injections, they need to be separated from their mother and hand-reared. Unsurprisingly, Paul soon falls in love with pups Caddy and Pitch when he sees them being cared for. The host also meets Sophie, a four-year-old cane corso, also known as an Italian mastiff, a breed known to have been used by Roman soldiers during wars.

The Secret Life of the Zoo, C4, 8pm

Zookeepers are concerned about pregnant elephant Thi as they believe she may be three months overdue. The risks for Thi and her unborn calf are growing by the day and the keepers are worried. Meanwhile, rampant male Rothschild giraffe Meru causes problems for the giraffe herd as he relentlessly chases the females, and male clownfish Polo gets injured while fighting with the other males for the attentions of dominant female Rosie.

Watchdog Live, BBC1, 8pm

Matt Allwright, Steph McGovern and Nikki Fox return with another series of investigations, including the flytippers dumping rubbish on an incredible scale who are caught on camera. A former fraudster known as King Con helps expose the big-name telephone company making it easy for scammers to hijack your phone number.

Dark Heart, STV, 9pm

Chris Lang, creator of the aptly named Unforgotten, is one of the best screenwriters working today. His latest involves DI Will Wagstaffe. “Staffe”, as he’s known to his colleagues, is haunted by the unresolved murder of his parents, which affects his romance with sometimes girlfriend Sylvie. He also receives moral support from sister Juliette and young nephew Harry. In the first episode, Wagstaffe investigates a murder, but soon learns that the victim, fortysomething Ray Collins, was arrested two and a half years ago on suspicion of sexually assaulting his young stepdaughters. As the crimebusters delve deeper into the crime, it’s not long before a lawyer, Guy Dawlish, is brutally attacked.