Brief Encounters (ITV, 9pm)

WHEN it comes to playing prim and proper then Penelope Wilton is your woman. Fresh from voicing The Queen in the latest version of The BFG, Wilton is taking on the Sheffield life of Pauline in 1982, who is happy to play second-string to her ambitious husband until the idea of organising Ann Summers' parties comes along.

Wilton recalls meeting two party planners during those days. "The party planning changed their lives. the thing about Ann summers for these woman and what our story goes into is that by dong these parties they became financially independent. It they'd been a stay-at-home wife, on the breadline, if the husband loses his job in the steel works, then you start making money. It changes the whole dynamic in the home. Suddenly, women found they were in charge of their own destinies. They didn't have to play the second role, as it were. One of them was in a very unhappy relationship and felt very put down, and belittled by her husband. she had three children and there seemed to be no way out for her. Then she started giving these parties and was able to leave him. Her children went to university, she married again and a whole new life started for her," says Wilton.

The actress was aware that these early parties were just for women. "No men. At the beginning of our story they're called prostitutes. Men didn't understand what it was all about. This sort of thing was very freeing for a lot of women, because it said that sex was not something that just men enjoyed," she adds. And filming Pauline's first party with the large sex aid, the hermit extender with remote control turned out to be extraordinary, says Wilton. "All the men in the crew went very quite."

She recalls as a teenager that her mother was extremely glamorous and her father was keen on fly-fishing.

"So they were seemingly a mismatched pair. They had books by the side of the bed and I suddenly saw Sex And The Older Woman among the fishing books. So I said to my mother, 'Mum, look, that book'. And she said, 'Yes, it's no use at all. the older woman is 38."

Tonight's episode starts with a recruitment fair at the community centre, Steph chats to the caretaker and agrees to go to his house to talk to his wife about hosting a party – a decision that puts her in danger. Dawn has to think seriously about her future when Russell tells her he can't cope with all the fuss she is making over their wedding preparations, while Nita puts her family first and gives Kieran an alibi for the hit-and-run. Drama also starring Sophie Rundle, Angela Griffin and Sharon Rooney.

How School Bosses Spend Your Millions: Channel 4 Dispatches (Channel 4, 8pm)

NOW he's settled for a less stressful job, many are reflecting on David Cameron's time at Number 10. He claims the expansion of the academy school system was one of the greatest achievements of his time as Prime Minister. With billions of pounds of taxpayers' money flowing straight into academy trusts, reporter Antony Barnett investigates the finances behind these schools, discovering large salaries and expenses. From the cost of new school uniforms to a US consultant on sky-high rates, this documentary lifts the lid on the academy expansion.

Forces of Nature with Brian Cox (BBC1, 9pm)

THE physicist concludes his journey by examining the effects of light interacting with the Earth, travelling to Iceland to witness a moonbow – the band of colours released when moonbeams are refracted by the spray of a waterfall. He then visits the site of an enormous outpouring of lava to explain why hot things glow red, and reveals how the different colours of light energy from the sun transform the plains of the Serengeti in Tanzania and drive the migration of humpback whales to the Caribbean each year. Last in the series.

Viv Hardwick