Secret Scotland, C5, 8pm

SUSAN Calman heads to the Highlands, where she searches for the Loch Ness Monster. She meets a man who has spent almost 30 years waiting for a sighting of Nessie, before having a go in a

home-made submarine. From the depths of the loch, Susan heads to Ben Nevis, discovering why the area is famous for its strongmen. Later, she tracks down the secret spot from which Bonnie Prince Charlie started the doomed Jacobite uprising.

Gogglebox, C4, 9pm

THE armchair critics are back for a 13th series, which is pretty impressive for a show that only started in 2013 – although it’s become such a TV staple that it does feel like it’s been around for longer. It’s certainly been on air long enough to turn some of the regulars into celebrities in their own right, but will any of the contributors tonight be belatedly sharing their thoughts on Steph & Dom: Can Cannabis Save Our Son? or, to keep it more topical, former Goggleboxer Sandi Bogle in Famous and Fighting Crime?

Score: Cinema’s Greatest Soundtracks, BBC4, 9pm

WHAT makes a great movie soundtrack? In this one-off documentary, elite Hollywood composers and movie-makers – including John Williams (Star Wars, Jaws), Hans Zimmer (The Lion King, Gladiator), James Cameron (Titanic and Avatar), Quincy Jones (Banning, The Italian Job) and Trent Reznor (The Social Network, Gone Girl) –give a privileged look inside the creative challenges making a score match the tone of a film.

Monty Don’s Japanese Gardens, BBC2, 9pm

THE horticultural enthusiast explores Japan during autumn. He begins as he did in the spring, at one of the “three great gardens of Japan” to learn how they are protected from the coming winter. Monty follows the history of the Japanese garden through the military strongholds of past leaders to the many styles, new and old, of the iconic stroll garden and finds a slice of Victorian England in the heart of Tokyo.