British Sea Power are regularly joined on stage by roadies dressed as bears – Ursine Ultra is a giant brown bear and Bi-Polar Bear is a snowy white.

But for the band’s most recent shows the bears have made way for brass.

In October the indie rock band convinced the five players in the Bournemouth Symphony Orchestra Brass Quintet to hop on a boat with their instruments and join BSP for a musical journey around Poole Harbour and a grand finale gig on Southsea Island.

“They were brilliant – they just turned up and got on with it,” says BSP’s Brighton-based guitarist Martin Noble.

The shows were not the first time the band have asked brass players to back them at a show.

Earlier this year the Sea Of Brass tour saw the 26-piece Foden’s Band – dressed in red blazers and bow ties – help the Cumbrian-born but Brighton-based group open a new venue in Kendal.

Every band which appeared on the tour – at De La Warr Pavilion in Bexhill, Sage in Gateshead, Durham International Festival – has been championship standard. But Foden’s were the only ensemble BSP didn’t need to rehearse with before they performed.

“We played with them in sound-check and then went straight into it. They had no nerves about breaking notes – they just follow the conductor and read the music – and it sounded amazing.”

Foden’s are currently rated the third best brass band in world, adds Noble, “they were s**t hot”.

In the 15 years British Sea Power have been together they’ve penned five studio albums plus two soundtracks. A third soundtrack – for Thomas Balmès’ documentary Happiness, a Sundance award-winning flick about an eight-year-old Bhutanese monk’s dream for a TV – has just been released.

But it was after BSP singer Yan Wilkinson contributed to an installation celebrating German artist Kurt Schwitters’ work at Tate Britain that the brass band idea took off.

After that show, Late, Wilkinson was invited to contribute to an installation in Derby. One suggestion was to collaborate with a brass band.

“We didn’t want to do it in an oompah traditional way,” reveals Noble. “We wanted something more complex and orchestral. So we got arranger Peter Wraight to add some arrangements on top of what we had already done rather than completely writing new arrangements.

“He completely transformed the songs.”

In the end the band never performed in Derby or at the Barbican in London – the latter show was ruined by a power cut. But they are hoping to rearrange the dates and record a live DVD and album as part of the Sea Of Brass project.

Before then they will bring the other half of their brass adventures to Wire’s Drill Festival.

The Bournemouth Symphony Orchestra Brass Quintet will join BSP and add their horns to tracks not featured on the Sea Of Brass tour.

Playing with only five extra musicians means going off piste does not spell disaster, explains Noble.

“The quintet is more adaptable. The players can quickly talk to each other and adapt mid-song if we extend a chorus or an ending goes on longer. With the big brass orchestras which are all reading from music they all get lost if you cock up.”

When the call came through from Wire for the Drill Festival slot the band pushed back plans to head to a Kent castle to record the follow-up to fifth studio album Machineries Of Joy (this is a band which has played at the Natural History Museum and on the Great Wall Of China).

“We know Wire’s music and we love the band, and once we realised the scope of the festival we just couldn’t say no.”

Another edition of much-loved BSP club night Krankenhaus will go ahead on December 19, with Brighton And Hove City Brass Band playing Christmas songs and Krautrock Karaoke to go with the full-on set by the band.

British Sea Power at All Saints Church, The Drive, Hove - Friday, December 5, 9.30pm