"Girls, the show about four twenty-something women navigating their lives “one mistake at a time” in New York City, is a cultural phenomenon in its home country and is set to be huge here, too.

It’s the creation of 26-year-old Lena Dunham, a person for whom the term ‘wunderkind’ seems regrettably underpowered. She put it together after her self-financed first film, Tiny Furniture, won best narrative feature at the 2010 South by Southwest film festival and brought her to the attention of Judd Apatow. He commissioned the show and, with Dunham, co-executive produces it. She not only writes and directs most of the episodes but also plays the lead character Hannah Horvath (and was nominated for Emmys in all three categories this year).

The show itself is so brutally realistic that it takes a second viewing before you can bear to drop your hands from your eyes and look properly, or start to laugh as hard as the writing deserves. To those of us – which is to say, all of us – reared on glossy, perfectly lit, gorgeously shot Hollywood couplings on the big screen and the more explicit but hardly more naturalistic small-screen versions in Sex And The City, the sex scenes are astonishing. And agonising. Almost every one of them shows the two rarest of all the televisual beasts – the realistic female body, and the unsatisfactory shag.

“What do you like?” pants Hannah’s on-off boyfriend Adam as he pounds away while she lies, faintly bored, faintly bewildered underneath him. “I like everything,” she replies, still clearly hoping that polite untruth will salvage actual intercourse as well as it generally does social intercourse. And if that exchange doesn't yank you back to your early years of sexual misadventure, naivety and mentally crucifying humiliations, the next one surely will. “Where do you want me to come?” gasps Adam. “What,” asks Hannah after a fractional pause, “are the choices?” Anyone further on in their carnal careers than Hannah at this point wants to throw herself prostrate on the floor and thank a benevolent god she never has to embark on that learning curve again.

Lucy Mangan on TV show 'Girls'