Here's something you probably didn't know about Portishead's Geoff Barrow: the guy's a proper hoot. You might expect the musician who had a hand in such claustrophobic classics as 'Sour Times' and 'Glory Box' to be deeply despondent.

But no – he's all chuckles and pithy put-downs. On his Twitter feed he even has a potshot at Coldplay. Another dispatch reads simply, profoundly: "I fucking hate hot air balloons". Is the rest of the group comfortable with such extrovert displays of jollity?
"The thing is," he says, in his yeasty Somerset accent, "I'm one-third of Portishead. My Twitter account in no way represents what Portishead is about. It's about me taking the piss in all kind of areas. Whether people like it or not, that's what I do. It's funny, I actually don't like social media at all. However, I can't help myself."
His screed against Coldplay, while clearly intended as humourous, contains glimmers of genuine anger. Does it enrage him to see bland, workaday groups lording it over other musicians?
"Massively yeah. I've never been any different. I've always felt that way. The difference is that, in my younger days, I was incredibly righteous about music. 'This is wrong, that should stop – they shouldn't be allowed make music, they're terrible'. You get older and you realise that, if you can find enjoyment in this world, you should seize the moments. Whether that be Coldplay or whatever… That said, everyone is up for ridicule – including myself. It's part of the game."
Since you're wondering, Portishead are indeed planning a fourth studio album. As to who, when or where it will manifest… obviously it's far too early to say. Notoriously meticulous, the band – which also includes singer Beth Gibbons and producer Adrian Utley – are at the bedding-in stage, tinkering with ideas, trying to form a sense of the sort of record they wish to make. Unless you’re doing it for a good reason – reasons all of you understand from the outset - what's the bloody point?
"We have this belief that, if we haven't got anything worth saying, we just don't say it. That might take ten years, it might take six or three. I don't think anyone really cares how long we spend on it. It might be annoying that there isn't a new Portishead record coming along. Hopefully people would prefer we took our time and write something worthwhile.
"Because Portishead saps your energy in a writing scenario, we don't see a great deal of each other outside of recording and touring. It's kind of like a computer game where there's a big boss waiting at the end. To take on the bad guy you have to run around and fill your backpack with energy. You go and investigate and it clicks and off you go."
They won the Mercury Music Prize for their 1994 debut Dummy, a project that seemed to crystallise all that was thrilling and important about the UK's then emergent trip-hop scene. More than anything by Massive Attack, much less also-rans such as Lamb or Morcheeba, it was the ultimate showcase for the movement: bluesy, drowsy, shot through, courtesy of Gibbons' banshee croon, with languid menace.
The band, named after Barrow's home town, formed in 1991. By then, he'd already honed his chops in the studio as assistant to Massive Attack on their first LP Blue Lines (the group gave him some free time at the mixing desk to work on his own ideas). Success arrived more or less overnight – soon not only was Dummy gracing the smarter stripe of dinner party, it was all over television. If a middle-brow '90s drama didn't feature at least a snatch of Portishead, it wasn't worth sitting through. Imagine, for instance, how ghastly This Life might have been without 'Glory Box' popping up at least once per episode.
This was all tremendously confusing for the group, then very young and very shy (to this day Gibbons declines to speak to the press).
"We never went to parties or award ceremonies," remembers Barrow. "We won the Mercury which was bloody uncomfortable – it proved a point to us, we weren't those kind of people. We never actively sought to be famous."
As for the ubiquity of the band's repertoire as incidental music – a trend that continues – well, frankly, Barrow would rather that weren't the case. However, the vagaries of copyright law mean that, in regards to television, Portishead don't have a huge say as to whether their songs are used or not.
"We generally don't work with corporations," he says. "Thing is, there's this blanket policy that means they can use up to a minute of our music. If opting out was an option, we would. But you don't have a choice – that's the way it is. We've made an effort not to saturate the market."
He isn't being falsely modest when he says he’s genuinely astonished Portishead have endured for as long as they have. Their second album Portishead arrived in 1997; after that it was a full 11 years until their next studio LP, Third. In between Barrow cultivated a side-career as producer, working with The Horrors and others. With that sort of release schedule, most artists would be quickly forgotten – somehow, and he isn't sure why, Portishead endure.
"We've very lucky in that we've got this 'sleeping dragon' scenario in our favour. We can go away for ages and people still want to see and hear us. That's very unusual. It's crazy - we get more live offers now than we ever did in that period we were supposedly 'huge' or whatever. We have a decent show ­— people want an alternative, so here we are I suppose."
Barrow's looking forward to headlining Electric Picnic. Portishead don't get to play Ireland half as much as they would like. For the past few years he's tried to arrange something – but it never quite came together.
"We've been trying to get over for bloody ages," he notes. "We'd wanted to play the Olympia, to do this or that, it never worked out."
He's matey and seems at pains not to come across as airy or pretentious. Still, under the bonhomie, you sense a steeliness. Promoting Third, Portishead had a much publicised run-in with the producers of the BBC show Later… With Jools Holland. Told their song selections were too loud, it was suggested they opt for a more low-key choice. The band were not for turning, grateful though they were to Jools Holland for all his support.
"Jools is amazing – we had our first chance on that show. We played 'Glory Box' and 'Wandering Star' in 1994 and the interest went crazy. What happened is they wanted us to play something else – our take was that we'd spent ten years away. To come back and be told what we could play… no thanks. We've never fitted into anybody else's kind of box. After all that, we're fucking sure not going to fit into one now."

Portishead play Electric Picnic on the Saturday.