Irish writer Sally Rooney won plaudits for her second novel Normal People last year, winning the coveted Costa Book of the Year award and a place on the Booker Prize longlist.

Many fans of the book - which charts the on-off relationship of young outsiders Marianne and Connell - were nervous when news of a TV adaptation was announced.

How could it hope to match the beloved novel? But it looks like their fears were unfounded, as critics have raced to praise the BBC Three adaptation.

In her five-star review, The Daily Telegraph's Anita Singh described the series - made up of 12 half-hour episodes - as "a rare treat, the TV drama that's better than the book".

She puts that largely down to the performances from the two principal actors, Daisy Edgar-Jones and Paul Mescal, describing both as terrific but singling out newcomer Mescal as he "has more to convey... it is a remarkable television debut".

The pair are at school together and we follow their journey through the awkward, self-conscious universal experience of first love, which is soon put under the strain of both peer pressure and the class divide.

The series dropped on the iPlayer in its entirety on Sunday and the first two episodes were then shown on BBC One on Monday evening.

The Guardian's Lucy Mangan gave the dramatisation of Normal People five stars, noting that "the show retains the pared-down approach of the book".

"It's a triumph in every way, from acting and direction to script, and if we see a better drama - certainly about adolescence, one which takes it seriously without treating it indulgently - this year, I'd be very surprised. It's a beautiful, hugely beautiful thing," she wrote.

It was another five stars from The Independent's Ed Cumming, who described it as "a beautiful, pitch-perfect adaptation that captures all the intensity and longing of the novel and will bring Rooney's work to the attention of those who don't know it, all five of them".

He also heaped praise on the "unassailable cast".

The Times's Carol Midgley, unlike most other critics, wasn't originally a fan of Normal People as a book, feeling that while it was "well-written... I wearied of the two main characters being mopey and navel-gazing. That's probably just as it should be, however. I am not the target audience; I am too old to remember being a shy, moody teenager, only a moody fogey."

She argued the TV version has added significant value to the source material, giving the adaptation four stars.

"Having watched this adaptation by Rooney and the screenwriter Alice Birch, I can say this without hesitation: this is one of those very rare occasions when the screen version thrashes the book. It is a beautiful piece of work capturing the fervid intensity of a first teenage sexual relationship with charm and poignancy."

The first six episodes of the drama are directed by Oscar-nominated director Lenny Abrahamson, who also directed the award-winning The Room, starring Brie Larson.

Hettie McDonald, who has directed episodes of Doctor Who and Howard's End, takes the reins for the final six episodes.

BBC Culture writer Sarah Hughes wrote in her five star review: "It's unusual too to find an adaptation that not only tells a story faithfully, but also builds on that story, making you want to turn back to the original source material and read it with these new images in mind. Normal People manages it triumphantly. Honest, tender, beautiful and heartfelt, it is surely one of the dramas of the year."

Eleanor Bley Griffiths, writing in the Radio Times, like many fans of the book, aired concerns about the TV outing: "Would it capture what I loved so much about the original writing?"

Luckily, "the answer is: yes."

That may have something to do with the involvement of Ms Rooney herself.

"Thankfully, when it came to transferring all this to the small screen, Rooney herself was on board to co-write the scripts alongside Alice Birch," Bley Griffiths notes.

She adds: "The casting is also absolutely spot-on, with particularly brilliant performances from the two young stars who are absolutely the versions of Marianne and Connell who live in my head."