Food cultures are meant to be shared.
Otherwise, you, as an European, shouldn't eat chocolate, corn, tomatoes, peanuts and sweet potatoes just to name a few, since none of them originate in Europe. This idea that only the indigenous people can prepare and serve their own "national" food is ludicrous. Spaghetti and pizza are Italian, French fries are (ironically) Belgian, so are waffles, croissants and baguettes are French, wurst and schnitzels are German, bean stew and white truffles are Croatian and so on. The point here is that most of the foods and products we consume originate someplace else entirely. But through immigration, trade and movement of people, we shared our cultures and that's why it's perfectly okay for a white British person to run an Indian restaurant, just as it's okay for an Indian to run an Italian restaurant.
Finally, if British people only ate their own "national" dishes, you'd be stuck with fish and chips and Yorkshire pudding, so...shush.