Meera Syal is one of Britain's best-known personalities of Indian origin. Awarded an MBE in 1997 and praised as one of the 50 funniest acts in British comedy in 2003, she will be speaking this month at the start of the Southbank Centre's National Treasures series ("Well, that's the end of my career, isn't it?" she jokes).

The talk is one of many to celebrate the 60th anniversary of the Festival of Britain. The programme is testament to the diversity that characterises British cultural life, ranging from multi-ethnic voices such as Syal's to an exhibition of memories of the original festival.

Celebrating the best of British raises difficult questions about national identity in today's political world, as it grows increasingly hostile towards multiculturalism. Syal, who made her name documenting the British Asian experience, is classed as a national treasure - yet only this year, David Cameron declared that multiculturalism in Britain had failed.

Syal's breakthrough was Goodness Gracious Me, the TV sketch series that she launched in 1998 with her fellow comedians Nina Wadia and Sanjeev Bhaskar. I remember watching it in my early teens. My own mixed family (half Pakistani and half English) was certainly in on the joke - from the mother who insisted she could make any dish better at home, to the young professionals baffled by the British obsession with "ethnic" wear. The magic of the show was that my white friends enjoyed it, too.

What has changed in the years since Goodness Gracious Me was made? "We caught the zeitgeist at a good time," Syal tells me. "A lot of the issues we were battling with through the medium of comedy - such as communication between the generations - aren't so sharp for younger British Asians."

Syal's later project The Kumars at No 42 was perhaps the natural continuation. Its format - a comedy chat show in which celebrity guests enter a fictional Indian family home - played on some of the same cultural disconnects as Goodness Gracious Me, but also highlighted the universality of family life. "Everyone's got an embarrassing family, haven't they?" she says.

The success of these programmes aside, can non-white faces become part of the furniture? Last year, Syal played Shirley Valentine in Willy Russell's play of the same name - a bold instance of colour-blind casting. "Ultimately it's about a female experience that everybody could relate to," she says. "I wish there was more of it."

She is unsure that the trend is moving in the right direction. "I watched the Baftas the other night and it really was a case of spot the non-white face. While the soaps and running serials are a fantastic banner for how Britain really is, the Midsomer Murders argument [the creator of this series said an all-white cast represented "the last bastion of Englishness"] was the tip of an iceberg. If you watch TV and do a headcount of other races, it is pitifully small.

“That's gone backwards. There was a time in the Eighties and Nineties when there was a real effort to include new voices. I don't think that's there any more."

It is difficult to know whether the change comes from complacency - a sense that we have moved past racism and don't need to make an effort to include non-white perspectives - or a wider discomfort with multiculturalism.

Cameron's speech, delivered in Munich in February, voiced such discomfort. "We do have to have an open debate about immigration," Syal concedes. "But the language he used in that speech was hugely disrespectful to the majority of immigrant groups, who have integrated. My parents have lived here for 50 years, have paid taxes and never drawn benefits, and chose to adopt British passports. You can't get more respect paid to your culture than that."

How do these matters appear in the arts?

“A lot of countries are grappling with what na­tion­al identity means. Britain is asking itself some important questions - we're still deciding whether our culture is insular. The arts are the most important place to ask those questions. I feel very blessed that I've had two rich heritages to draw from, which has produced some very interesting creative challenges. It's not an easy process, but I don't think anything interesting is easy." l

Meera Syal will be speaking at the Purcell Room, London SE1, on 28 June. For more details visit: southbankcentre.co.uk