Mutilated rodents. Deadly airborne diseases. Accidental infant death. Torture devices. Recreational drowning of cats. All across the land, small children are flicking through picture books, or lying under their duvets being lulled to sleep by nursery rhymes, but underneath the words in those innocent-seeming singsongs often lurks some pretty grim subject matter. That’s exactly what made them so appealing to musician Bill Wells. Those traditional, much trotted-out lyrics are sugar coated in soporific, catchy melodies so they pass for innocuous kids' songs, and all the while grotesque images are festering just below the surface.

“I like the idea of re-evaluating the lyrics - taking some of the best known songs around, but letting people really listen to them for the first time,” says the Falkirk pianist and experimental composer, whose latest album, Nursery Rhymes, rearranges 18 of many people’s childhood anthems into twisted jazz piano covers.

Wells has arranged and performed plenty of cover versions in his time - ‘God Rest Ye Merry Gentlemen’ and ‘Jingle Bells’ had makeovers on his National Jazz Trio of Scotland’s Christmas Album; he and Isobel Campbell reconfigured Billie Holliday songs on their Ghost of Yesterday EP; and he’s reworked various pop songs including Bananarama’s ‘Cruel Summer’ and Jennifer Rush’s ‘The Power Of Love’ with his frequent musical other half, Aidan Moffat.

In fact, it was just after winning the inaugural Scottish Album of the Year Award in 2012 with Moffat for Everything’s Getting Older that Wells was given a £30,000 artist bursary award from Creative Scotland. Generous soul that he is, Wells chose to share the wealth and recruited some of his favourite artists to join him on the Nursery Rhymes project. (If proof were needed of his own very unstarry requirements as bandleader/ arranger/ pianist/ conductor and chief-emailer, he booked himself, admittedly by accident, into a cheap Brooklyn flat over an hour from the recording studio, which his taxi driver told him was, “in one of the most dangerous neighbourhoods in New York.”)

“You’re not gonna jet off to the Bahamas with the money really are you?”, says Wells, with a small laugh that vibrates his white beard. “Not if your life is doing this. Making music I mean. You think, I’ve got this chance to make this amazing thing, to do something really big, and to be in a position to pay people properly.”

So he assembled his very own jazz dream team in New York, including members of Yo La Tengo, Deerhoof, Teenage Fanclub (Norman Blake also produced the album) and a few musical heroes who he’d been looking for an excuse to work with.

“Karen Mantler was always a priority to get involved,” says Wells, referring to the New York singer and musician that he’s been a fanboy of since first hearing her sing as a nine-year-old on her mother’s 1971 album, Escalator Over The Hill. A sprawling jazz opera by bandleader Carla Bley, featuring Don Cherry and Linda Ronstadt amongst scores of others, Wells describes it as, “a magnum opus, so crammed with great ideas and really interesting guest musicians.”

The child singer went on to run her own record label and form her own ensemble. “There are certain people you just know you’ll buy everything they do, she’s one of them.”

Wells pitched his nursery rhymes idea at Mantler, she said yes, and now can be heard all over the record, playing hammond organ, chromatic harmonica, glockenspiel and singing, with particularly smoky-sugary success on Three Blind Mice. “I wanted someone a bit unknown, underrated, but also brilliant.”

Elsewhere Satomi Matsuzaki from Deerhoof gives a sinister celestial spin to her Japanese language version of Twinkle Twinkle Little Star; John Peel favourite Bridget St John unearths a more morose and unsettling side to Ding Dong Bell (in the voice of ‘a child who tortures animals and grows up to be a serial killer’, as she puts it), and Belle & Sebastian member turned solo artist Isobel Campbell does something discordant and milk-curdling to Polly Put The Kettle On. It’s not all dark and disquieting stuff to bring on tears at bedtime though; Norman Blake’s warm, recognisable Teenage Fanclub vocal blends more melodically with Georgia Hubley’s on Lavender’s Blue, wrapping around the jangly surf rock bass and guitar of her Yo La Tengo bandmates, James McNew and husband Ira Kaplan.

As for Wells’ initial mission statement about revisiting the coded, often violent, sometimes funny messages beneath the rhymes, he’s created an interesting and unexpected curiosity - revealing veiled lines about everything from the sights seen on the final death march to the guillotine or gallows (Oranges and Lemons) to the threat of the yellow fever mosquito (Shoo Fly).

“It’s funny - I’ve done a lot of covers, and yet I still realise that 99.9% of the time, it’ll only be second best to the original version. A bad cover, to me, is basically just some pretty uninspiring karaoke. A good cover is something that lifts the original arrangement, adds some new personality, and ends up with something fresh. Hopefully that’s what we’ve done here.”

“I’m a huge Beatles fan, so for example am very wary of a lot of Beatles covers, knowing I’ll probably hate them,” he laughs. “No-one’s really going to come out and say Humpty Dumpty is their favourite song, so I suppose I’m less likely to annoy someone by covering it, aren’t I?”

Nursery Rhymes is released on 20th November on Karaoke Kalk.