The BBC drama about a couple in their 70s may not change the treatment of older people but at least it depicts two real, healthy and sane lead characters, says Lucy Harmer of Age UK

After retirement, relationships often change: we see quite a high number of divorces among older people. I get the impression there's also a growing number of marriages, too, so I liked the premise of this series, about two people in their 70s, Celia (Anne Reid) and Alan (Derek Jacobi), who arrange via Facebook to meet. They almost got together as teenagers, but haven't seen each other for 60 years; after one date, they decide to marry.

The fact they get engaged so quickly did strike me as pretty preposterous, but I loved the way the programme showed them using Facebook. Internet use among older people is still low – only about a quarter of people who are 75 and over have the internet at home – but a growing number of older people are using social media, so it's great to see a programme treating it as quite normal. We got a lovely sense of the tension that surrounds arranging their date online, just as you would with a young couple.

That's the best thing about the programme, really: Celia and Alan are depicted as normal, healthy and sane. All the silly, entertaining drama lies in the lives of the people around them – Celia's daughter is having a lesbian affair, while Alan's daughter is accused of killing her husband. Ageism is one of the last non-taboo prejudices people see on TV: we did some polling last year that showed people over 65 felt TV depictions of their age group were patronising. Older characters are often vulnerable and frail; here, we have two real, rounded individuals. Even Alan's heart problems aren't holding him back.

It's tempting to see this programme – along with Hilary Boyd's novel Thursdays in the Park, and the film The Best Exotic Marigold Hotel – as part of a groundswell of more realistic cultural depictions of older people. I'd like more examples before saying there's been a real change, but I certainly welcome anything that goes against the grain of our youth-centred popular culture.

• Lucy Harmer is head of Age UK's information and advice service. Last Tango in Halifax is on BBC1 on Tuesdays