Pete Doherty swings into the room, puts his beer-bottle down and takes off his battered Raskolnikov-style coat before removing his blue sweater and his T-shirt, too, without embarrassment.
A brief glimpse of the former Libertines frontman's tattooed torso and scarred belly reveal the ravages of his 32 years. He quickly replaces his T-shirt, which had been inside-out, and begins posing moodily for photographs, in a room littered with strange objects: taxidermy, antique furniture and canvases. Is this for a music video? Has he got an album coming out? No. It may look pretty rock'n'roll, but it is, in fact, the start of Doherty's bid to be taken seriously as a fine artist.
Jumpy like a cat, Doherty shows me around London's Cob Gallery, where his first UK solo art exhibition (he showed work at the Chappe gallery in Paris in 2008) will open next week. Most of the artwork is yet to arrive, but nine canvases are scattered around the black-walled, underground space in Camden. The paintings are spare, with lots of white space showing through linear outlines, glued-on paper and Doherty's spidery scrawl. Their unifying feature, apart from the artist's signature, is that they have been painted in blood. Doherty's blood. It is a technique he refers to as "arterial splatter": an ex-girlfriend's father coined the phrase. The streaky, brown-ish marks, by turns thick (as if he's just swished a bloodied thumb across the surface) and bespattered (he squirts his blood from a syringe) are unmistakably human.
A further 20 new blood-paintings will be shipped in from Paris, where the singer now lives, to form the top half of a collaboration between the curators of Cob and another gallery, Guts for Garters. The show is called On Blood: A Portrait of the Artist. The first part of the title refers to his blood paintings, and the latter half to a decision by curator Cassie Beadle to exhibit a selection of strange curiosities, trinkets and detritus hoarded by Doherty over the years.
Painting is something of a collective process for Doherty. A "fucking accurate" portrait of his friend Peter Wolfe, from the band Wolfman and the Side-Effects, was drawn by his friend Alizé Meurisse, and Doherty has added a splatter or two and some song lyrics into the mix. An early portrait of The Libertines, which the artist modestly disparages, has been added to, not only by his eight-year-old son Astile, but also by his good friend, the late Amy Winehouse, who drew a small self-portrait in her own blood.
"She was on the phone to her dad when she did that. She said, 'Dad, I'm with Pete and he's making me draw with my blood!' He didn't like me much, her dad."
The actress Charlotte Gainsbourg added a sketch of a house to a painting called Leet Strife – a less pretentious title than "Street Life", he says.
Doherty explains that for his newest works he has been using watercolours. He says it is the only way he can begin to replicate the "emulsive, wishy-washy residue on the neck of a crack-cocaine bottle". Alarmingly, he then reaches into his pocket and pulls out a broken crack-pipe ("It's an old one, I promise") and holds the glass up to the light so I can see the silvery remains of the drugs.
"Look at the colours, the oranges. You see that there? You can only get that with watercolours."
Marc Quinn made wonderful sculptures from his own frozen blood, but is there something a bit faddy and pretentious about painting with it? I suggest that the self-harm element might be rather gruesome, but Cob curator Victoria Williams has an intriguing take on it. "It's about breaking down the boundaries between yourself and your art. I don't think it's destructive, it's quite giving actually," she says. "It's certainly not about gore."
Later in the day, the curators, Doherty and his manager are getting ready to drive a van to Wiltshire, to the mansion the artist used to rent from Lord Cardigan but vacated after the roof fell in. There is some anxiety, Doherty having arrived over an hour late, that they will not get to rifle through the storage container there until after dark. Doherty is rather apprehensive about what they will find.
"Everything flooded when the roof fell in," Doherty says. "Then it froze, then it flooded again when it melted. We stuck everything into storage but lots of it was ruined. Have you ever seen mould that looks all fluffy and white like snow?"
I haven't. Nor have I met Doherty before, although he insists that I have: that famous face, his dishevelled hair now touched with grey, eyes outlined by lack of sleep and a smirking, disarming smile.
The curators have quite a task ahead, sifting through the piles of "silks, bones, leathers, skulls, palettes – what's that thing you put canvases on? – oh yeah, easels, frames, boots, laces, wigs, mannequins..." that are, apparently, Doherty's passion.
His proclivity for hoarding leads him to talk about his infamous on-again, off-again relationship with the supermodel Kate Moss, from whom he finally separated in 2007.
"Kate used to collect elephants, so I'd buy them for her wherever I went," he says. "When we split up she destroyed all my stuff, but she didn't destroy my elephants. Because I couldn't get over her for a while I just kept buying elephants and now I've got a huge elephant collection for sale. I might post them anonymously to her as a wedding present."
Despite Moss having married her long-term boyfriend, Jamie Hince, last July, her name is rarely printed without mention of her tempestuous relationship with Doherty. The singer's penchant for heroin and crack-cocaine led to the end of their relationship and the model's association with him dented her reputation and helped to earn her the epithet "Cocaine Kate". Moss publicly split from Doherty after footage of her allegedly taking cocaine at a studio where he was recording with Babyshambles was sold to the press. Prosecutors decided not to charge the supermodel, in the absence of forensic or direct eyewitness evidence, but Moss lost contracts with H&M, Burberry and Chanel before admitting herself to rehab.
I ask Doherty if he has any regrets about the demise of their relationship. He is silent for a long time: "I suppose I must have, but I was a bit unhinged at that time," he shrugs. "The drugs. The thing is, she knew from day one when we began our relationship that I was using very heavily. She knew that. So, you can't suddenly turn around and say, 'you've got to stop all that'. I do have regrets about Kate, but I wouldn't want to talk to you about them. I'd only talk to a highly skilled doctor with large amounts of morphine and a hypnotherapist. And a small monkey."
He laughs and then lets out a scream before putting his finger in his mouth. He has cut it on the broken crack-pipe in his pocket. He bleeds only slightly, but it's a sign that we need to talk about something else. I joke that I've got some paper in case he wants to make a drawing. He declines, the mood having dropped, and for a moment the connection between his art and his well-documented self-harming hangs in the air.
The show is a chance for Doherty to revitalise his image in the wake of his many falls from grace. In 2003 the singer was ejected from The Libertines, at the height of their success, by his one-time best friend Carl Barât, thanks to his increasing dependence on Class-A drugs. Doherty went on to front Babyshambles, with whom he released two albums, and also produced a solo record called Grace/Wastelands in 2009, but his celebrity reputation has always rather eclipsed his music. In 2010 The Libertines reformed for appearances at the Reading and Leeds Festivals – but, as the release of Roger Sargent's film about the band's revival, The Libertines: There Are No Innocent Bystanders, released next month, reveals, with Doherty the appeal of the story is usually greater than the sound.
Doherty has been in prison three times, had at least 15 court appearances, a conviction for burglary, more than 26 drugs charges and is currently on bail for cocaine possession. I ask how he is managing his addictions.
"I've stopped injecting," he says, giving credit for this improvement to a new girlfriend, whose name he decides not to disclose, but whose parents he is meeting at their Oxford home this evening.
"The only way I see myself in a serious relationship is if I am toning it down a bit. When you're banging up all day you can't really have someone else in your life, especially if she's an English rose. I wouldn't let her touch anything, I just wouldn't." Doherty tells me he is being treated at a walk-in clinic for users and is currently on a pharmaceutical opiate called Subutex ("Posh and Becks, as they call it"), which "doesn't get you high" but suppresses withdrawal symptoms.
Gone is the implant which he had in his stomach to block the effects of heroin. "Jesus Christ, thank God them days are over. That was when I was up in front of a judge every five minutes and he was saying, 'get clean or go to jail'". Doherty had quite a hard time in prison.
"I got on OK in Pentonville [in 2006] because it was kind of my local, if you like. A lot of people wanted to get me, but more wanted to do me a favour. In Wayland last year it was lads from east rather than north London, and loads of other places. People I didn't know." As soon as he arrived, he says, people started getting at him, requesting money and drugs for protection. "I didn't have any money, I didn't have any drugs. One guy said he was going to stick a fork up my arse. I threw my telly at him because I thought that would get me put in isolation."
Instead, they moved Doherty to another wing where he found an ally in his cellmate who "didn't like bullies, basically". Between them they managed to fend off the attention. "A lot of those guys are just scared little boys inside. If you stand your ground they back down."
When Doherty speaks it comes across that the constant danger, the addictions, and the hell-raising parties all stem from his wish to emulate the bohemian ideal. This was clear in his Libertines days, when the band's red jackets and the presentation of Doherty as a kind of Nick Drake of our times – a new romantic, a poet and a rebel – were still doing their work.
A decade on, the figure who describes quite eloquently and earnestly his passion for a time when men wore smoking jackets and when drugs and art were synonymous, seems deflated. I hope that the art will be a positive step for Doherty; his enthusiasm for it recalls the old Pete – the showman and the optimist.
"I have a distinct memory of friends I had at school whose parents were, for want of a better word, bohemian. That was the kind of England that I thought I should have belonged to," he says. Instead Doherty grew up in a series of barracks, the son of a Catholic Army Major, and received little encouragement for his creative pursuits.
"My family used to say, point-blank, 'We'd support you if we thought you could sing, or we thought you could write songs, but you can't'."
Last year his widely publicised estrangement from his father ended after a good meeting at his little sister's wedding. "The family was all there together and I think my father was a little bit surprised at how compos mentis I was. He turned around and said that I was welcome to come home for Christmas. That was the first time in six years he's said that."
Repeated flayings in the tabloid press from 2005 onwards – his fans loving his Keith Richards-esque behaviour, his detractors revelling in his destruction – took its toll on Doherty. Never mind the fact that he courted it to start with. Three years ago he upped sticks to Paris to avoid the relentless attention. He loves it there, his own modern-day bohemia.
"The media circus got a bit twisted when I was in London. It became a bit of a joke, really. In Paris, they're so serious I can take myself really seriously too. I can get really morbid without people telling me to cheer up." He still has a loyal fanbase and he hasn't abandoned his music. He has already played a couple of secret gigs in London this year.
Despite this retreat from public life, Doherty hit the headlines earlier this week when the South African supermodel Lindi Hingston told the South African Sunday Times that she had given birth to his baby six weeks ago. Pictures of the little girl, who has been named Aisling, appeared in the paper. There is a distinct Doherty pout to the baby's features. When I ask the man himself about the pictures, he claims not to know anything about the press coverage.
"I'm really surprised she's done that [talked to a newspaper]," he says rather sadly, looking to his manager for confirmation and support. "The little girl was two months premature. I said I'd try to be there for the birth. You know what, I don't want to talk about that." So she is your daughter?
"Yeah, she's mine," he says, adding: "We're using the baby's blood in one of the pictures". I'm almost certain he's joking. Almost.
On Blood: A Portrait of the Artist, Cob Gallery, London NW1 (cobgallery.com/ gutsforgarters.com) 26 February to 4 March