John Williamson charts the progress of Mogwai as they head for Rothesay to unveil their new album.

Rothesay on what will most probably be a typically wet bank holiday weekend is not where most bands would choose to preview their new album, but the album in question, Mogwai's third and the first for the new Southpaw label, 'Rock Action', is worthy of such special treatment.

Far from the lengthy instrumental opus that may have been expected, 'Rock Action' is eight tracks long, features some singing from Stuart Braithwaite and guest Gruff Rhys from Super Furry Animals, has smatterings of brass and strings, only the occasional burst of trademark noise, and lasts for less than 39 minutes. To Mogwai, confounding expectations is a duty.

"When we finished the recording for this album," says Braithwaite, "we had the best part of 22 songs, but equally we realised that releasing another double album would just be falling into all the traps that have been set for us: it would have given the people who don't like the group ammunition for years. We wanted to do something concise, because we realised that all the really great albums, such as Leonard Cohen's Songs From A Room, are less than 40 minutes long."

The new label and new approach may suggest that 'Rock Action' is the album that Mogwai have always aspired to making, but have previously been restricted by their own expectations and lack of cash, but this is something that Braithwaite is keen to repudiate.

"I think the problem is that we never thought we would make an album in the first place," he says, "so it is difficult to see this as the realisation of everything we have wanted to do. I think the first album displayed all the hallmarks of a band that didn't know how to make an album, but with each one there have been some mental steps that we have taken and changes to the whole process that have made them better. Obviously, having more resources for recording and promotion makes things easier, but I don't think that has much impact on the music."

"Also," he continues, "it was only when I started reading the reviews that I realised how different this album was to the previous ones. When you are so close to something you don't realise the changes - we tried a lot of things, and not all of them worked, but I guess this time we left out the ones that didn't. When you start involving brass and violins and singing, sometimes things that sound like a good idea turn out to be pretty farcical."

The brevity and more conventional song structures, coupled with the extra resources of a bigger label, are perhaps the characteristics most likely to endear Mogwai to a wider audience this time around, but already there is evidence of the kind of sniping that usually accompanies the transition of underground bands into a more mainstream arena. The Wire has dismissed 'Rock Action' as the work of a band "who have backed themselves into a corner. Instead of coming out fighting, they're attempting to slip out quietly while everyone's looking the other way". With the other reviews being largely favourable, it would appear that Mogwai's success remains a problem for many.

"One of the reasons we wanted to change things about is that there are plenty of bands kicking around now who sound like we used to, but I am more disappointed than upset or surprised by that type of review. I think The Wire is brilliant at missing the point of great music. I love a lot of the music that they write about, but it is done in such a middle-class, detached, and fanciful way that it does little to promote the music they are writing about. For me, making music is about moving people and, as a listener, about being moved, not about diminished sevenths.

"I think we have done a lot of things that would upset people coming from that kind of angle - supporting the Manic Street Preachers or playing at Reading - disapprove of, but to me it is about a chance to get what we are doing across to new people, not just a small clique of journalists or fans."

For, while Mogwai may appear to be moving towards the upper end of the album charts, there is still much to distinguish them from any of the masses of uninspiring major label-funded "indie" rock that is as close to alternative as you will find in such places. Take their imprint label, also called Rock Action, and Saturday's inspired but almost certainly non-viable concert on the Isle of Bute.

"One of the main reasons for signing to Southpaw was the chance to develop the Rock Action," says Braithwaite, "and to put out records by other bands. In the past that was a struggle and very much a case of doing when we could afford it and sitting in my bedroom folding the sleeves and putting them into plastic bags. Now I don't really have to do anything except find the bands - Southpaw have the distribution and marketing back-up."

The first Rock Action release by Edinburgh band, The Zephyrs, sold out its pressing of 2000, and future plans include releases by Glasgow's James Orr Complex and what Braithwaite describes as the "drill and bass" of Random Number.

The Rothesay extravaganza, which takes place tomorrow and for an £18 ticket includes travel from Glasgow to Bute and back, a show at the Rothesay Pavilion, and a late-night club on the Renfrew Ferry when the 500 ticket-holders return to Glasgow around midnight.

Another example of the importance they attach to giving value for money? Not particularly, as Braithwaite would have it.

"I don't want to get on my high horse, because in a few months' time we will be back and playing in all the barns," he laughs, "but for most people this will be the first time they will have heard these songs, and I want it to be special. I've never been to Rothesay, but other members of the band went there on holiday as kids, and I just want to recreate the atmosphere of shows I went to at the Ayr Pavilion when I was younger. The whole thing that made it special was the journey, the hanging around, and the drinking cheap wine while standing in the queue."

Even before the release of 'Rock Action' in this country, Mogwai have completed the first of what will be several US jaunts this year, and find themselves at No 2 in the international chart in Japan, where they sit between dinosaur rockers Bon Jovi and Aerosmith. For Mogwai, 'Rock Action' will be the bridge that takes them from the Rothesay Pavilion to arena-sized venues.