They're almost royal – and certainly funny, but a new TV show is accused of mocking the trusting nature of Americans

The series has become BBC America's highest-rating comedy show

Ed Gamble and Amy Hoggart star in Almost Royal burning bright productions

Meet Georgie and Poppy Carlton, distant heirs to the British throne, who have escaped the privileged existence of their country pile to travel across America for a crash course in the "real world". But these clueless aristocrats are actors and the television show following their "nice but dim" antics has become a cult US hit, leaving some Americans unhappy that their inherently trusting nature been abused.

Georgie (Ed Gamble) and Poppy (Amy Hoggart) are the stars of Almost Royal, a spoof comedy show, produced and screened by the BBC America channel. Seizing upon an American fascination with the British aristocracy following the success of Downton Abbey, Almost Royal follows the sheltered siblings, "50th and 51st in line to the British throne", who are fulfilling the dying wish of their father, Lord Carlton, by travelling across the States to investigate how ordinary folk live.

Poppy, who some viewers may have confused with Pippa Middleton, has hopes of finding fame as a lifestyle guru or cookery presenter despite her delusions being frequently exposed. In Los Angeles she asks a plastic surgeon: "Can you make me look less like my mother?"

She asks an unsuspecting Texas ranch-hand, with apparent sincerity: "What made you want to become a cowboy? Was it Toy Story 1 or 2?"

Georgie, seeking the life-skills which will help him manage their Norfolk estate, is shown how to swing a baseball bat in Boston and says: "Our father used to keep this sort of thing in the car in case anyone came to wash the windscreen." He explains their chances of ascending to the throne thus: "If 49 people in the line of ascension to the throne all decided to go on the same bus holiday and that bus went off a cliff, then I would be king."

The series has become BBC America's highest-rating comedy show; it had its premiere a fortnight ago. It is the first BBC Worldwide comedy to be sold back to a UK broadcaster: E4 has bought the series and will be screening it this autumn.

Yet some Americans are uneasy that the series has exposed a cultural genuflection towards anyone claiming to be British royalty. A Los Angeles Times reviewer complained: "For all our cosmopolitan make-up, we are a parochial people; but we are also a trusting people, willing to take everyone at their word … We tend to suffer fools, if not gladly, then with impressive patience."

Variety said: "The idea of foreign visitors asking their US hosts impertinent or insulting questions, and making the latter look gullible in the bargain, would seem to be pretty well exhausted." But the influential Hollywood publication praised the "frequently funny" show: "Gamble and Hoggart manage to strike just the right tone, sounding alternately wide-eyed and priggish, without coming across as mean-spirited – which is no small feat."

Almost Royal, which built a large social media following through YouTube clips before it aired, has fared better than another US attempt to cash in on the Royal Family. Fox's I Wanna Marry Harry, a dating show in which 12 girls compete for a Prince Harry lookalike's affections, was axed due to dismal ratings, with its remaining episodes shunted online.