You're doing very well telling them apart," Amrit and Rabindra Singh's elderly father remarks as he watches me talk to his daughters. "I still get them confused." The identical twins, dressed in matching Punjabi outfits, right down to the earrings, necklaces, bangles and jewelled bindis in the centre of their foreheads, smile indulgently at his joke. Even their laughter sounds the same. But these Sikh sisters long ago stopped worrying about being mistaken for each other and have turned being twins to their advantage. They have made it part of their brand in the art world, where they are known and celebrated as one artist: the Singh Twins. Their style is a fusion of Indian tradition and contemporary Western influences which they label "past modern". Each canvas is produced jointly and combines the bright colours, intricate designs and flattened perspectives of intricate Indian miniature paintings with modern political, social and cultural themes. Among their best-known are From Zero to Hero, featuring the Beckhams, and Art Matters, a piece commissioned to mark Liverpool's tenure last year as European Capital of Culture, but Singh Twins' works are to be found across major national and international collections. In 2002, they were only the second British-born artists, after Henry Moore, to be accorded an exhibition at New Delhi's National Museum of Modern Art. And the windowsill of their neat, calm, book-lined studio, next to the family home halfway up a sandstone hill between Birkenhead and the Irish Sea, is lined with awards that are sparkling in the spring sunshine. "One thing that might help," offers Rabindra, as I once again address her as Amrit, "is that I tend to find myself, almost subconsciously, standing on the right." Indeed, the reddish shawl each wears is, helpfully, over her right shoulder and Amrit's left until the photographer mentioned it and Rabindra duly moved hers to match her sister. There is undoubtedly an element of playing with hapless visitors' confusion over which is which, but the twins regard their shared identity, I quickly come to realise, as more than a game or a marketing device. They have turned it into something to highlight the tensions they have encountered, as citizens and as artists, in being both British and Asian. "Western contemporary art is all about the individual, the inner self," reflects Amrit, the more talkative of the two, as the three of us perch at the end of the long studio table where their latest painting – based on events in Palestine and looking at the impact of politics on everyday lives – lies half-finished. "So in Western art, it doesn't matter if anyone else understands the work, as it is about the individual artist and what they are feeling. This was certainly the view when we were studying art at university [from the mid-1980s until 1991 first at University College, Chester, later Manchester]. We were constantly being told that to be individual was healthy, that we had to be more different from each other, be influenced by different Western artists from each other, but that didn't seem valid to us. From the point of view of Sikh, Indian or even Asian philosophy, the community comes first and the individual is second." The clash between the two codes, say the twins, left them, like many other British Asians, under sustained pressure to abandon their cultural heritage. Their final degree grades were even reduced because they wouldn't yield – though they subsequently had the marking overturned after a seven-year battle with academia. The prejudice they encountered – at one stage an examiner was reported to have remarked, "Give them a 2.2, they won't mind because they'll soon be in an arranged marriage" – might have broken some, but it brought out the rebel in the sisters. "It was when we were at college," Rabindra recalls, "that we started to deliberately wear the same clothes to challenge the notion of individuality. We'd always had the same clothes, but until then had not necessarily worn them on the same day." They see their art, too, as a challenge to questions of identity and what is acceptable or fashionable. It favours narrative, detail, colour and time-honoured techniques – none of which are qualities likely to see them lionised alongside their contemporaries, the Young British Artists. Yet it is also very modern and even edgy because of its exploration of what it is to be British and Asian simultaneously. "We were told by our tutors that the miniature was outdated," Amrit remembers. When they first wanted to exhibit, they would routinely receive "nice letters, saying how much they liked our work, but perhaps we'd do better in an ethnic gallery in the East End of London". They have, with their success of the past two decades, turned the tables – though they feel that a "London, art- establishment elite" continues to look down on their work because of its traditional Indian roots. They decided early on not to sell their works in order to build a touring collection, but do accept commissions and have, of late, allowed some pieces to go into national collections. But it is hard to say what their paintings would command on the open market; substantial five-figure sums are mentioned by dealers. Though they are "twin-dividuals", they insist, the Singhs spend 99 per cent of their time together. They simultaneously discovered a passion for Indian miniatures aged 13, while spending a year travelling with their father around his native Punjab. They jointly devise and execute most of their works, their skills interchangeable. "We could probably tell which of us has done which part, but otherwise only those very close to us could work it out," says Amrit. Some pieces, especially in the various series they have completed on particular themes (such as "The Hart Project" and "Facets of Femininity"), are wholly by one or the other. "But we don't see it as my work, your work," Rabindra stresses. "It is not that we can't do things on our own, but this is a joint venture. Our thinking, our ideology, our political-social outlook is identical." She does concede that the sisters have different characteristics. "I am a perfectionist, which is not always a good thing, and Amrit is the one who gets it done." But they also say the last three words in harmony. Their mode of working, the twins point out, has parallels in the medieval age, when monks would work together on a single illuminated manuscript. And there is something rather monk-like and self-abnegating about the Singh Twins. For all their warmth and humour, they continue to see themselves as outsiders and are more comfortable talking about their work than themselves. The twins' Sikh father came to Britain when he was nine. They were born in Richmond, Surrey, but moved to the Wirral when they were still small and encountered what they describe as low-level racial prejudice as youngsters – name-calling and, on one occasion, a brick through their window. Though now in their early forties, they continue to live in the extended family home with their father, uncles and cousins. They used domestic settings a lot in their early work – part, as Amrit puts it, "of celebrating the more positive side of the traditional Indian lifestyle rather than girls locked in their bedrooms and forced marriages". One of their best-known works is based on the wedding of their elder sister, Nyrmla. A print of it is propped up at the entrance to the studio. Typically, it includes both the traditional ritual of the bride's hands being henna-ed with images of globalisation and reminders of consumerism in the Power Ranger toys lying on the carpet. "There is always," says Rabindra as we study it, "a serious message in our work – which includes saying to youngsters who are going through similar pressures to the ones we experienced as teenagers that it is OK to explore your Indian identity, that you can be British and Asian, and have the best of both worlds."