The Merchants House of Glasgow doesn’t immediately strike the first time visitor as ship-like. August, with its walls lined with portraits and historical detail, it might not appear like a natural jazz venue either but the grand hall of this largely unsung building on West George Street, directly opposite Queen Street Station, has indeed proved to be an excellent home for a monthly jazz series since the beginning of the year.

And now it’s going to be a ship, metaphorically speaking, as saxophonist Paul Towndrow takes his multi-cultural orchestra and its Merchants House audience on a voyage from Glasgow to New Orleans to Kolkata with his latest composition, Deepening the River.

Part of the Festival 2018 celebrations that accompany Glasgow’s hosting of the European Championships, Deepening the River had its genesis in the very venue where it will be premiered, as Towndrow explains.

“I didn’t really know about the Merchants House because it’s a bit of a hidden gem. You can easily walk past it and not even imagine what’s behind that door on West George Street,” says the saxophonist who, as well as leading his own groups, is a long-serving key figure in the Scottish National Jazz Orchestra. “Then I was lucky enough to become involved in helping to curate the Jazz at Merchants House series and discovered its grand hall has a lovely acoustic, a great piano and a wonderful atmosphere.”

Around the same time as the jazz series was being discussed last summer, applications were being sought for projects to become part of Festival 2018. Towndrow noticed that a lot of the events being planned were taking place in George Square, which some of the Merchants House’s rooms overlook, so he began researching the Merchants House’s history as one of Glasgow’s oldest and most important bodies.

Among the many projects the Merchants House has been involved in down the centuries was the scheme to develop George Square. This tied in with Towndrow’s thinking and when he realised the Merchants House played a central role in making the River Clyde navigable for shipping, thus facilitating the growth of Glasgow as a city with trading links all over the world, he had a name and a general concept for his composition.

“I thought this was a great opportunity to write a piece of music for Glasgow and its people,” says Towndrow, whose previous compositions have included Pro-Am, written for two jazz orchestras to mark Glasgow’s hosting of the Commonwealth Games in 2014. “The idea was to use the deepening of the River Clyde as an analogy for potential and for opening up communication and the mixing of cultures and promoting tolerance, all the things that music stands for, or should stand for. Of course, if you look into everything that followed Glasgow opening up to international trade there are darker elements as well but essentially there’s a lot to celebrate.”

For Towndrow, Glasgow’s music scene is currently enjoying a creative boom with musicians moving freely between genres. He cites the Grit Orchestra, where players from traditional, jazz and classical music work together very easily, as a great example of cross-pollination. Having taken Glasgow, New Orleans and Kolkata as his starting points he has brought together musicians from jazz, Scottish traditional and Indian classical backgrounds to form the orchestra that will perform Deepening the River.

“Great things can happen when musicians don’t restrict themselves to their own musical styles,” he says. “Jazz has always been about mixing genres – that’s how it began in New Orleans – and there have been numerous examples of jazz mixing with folk music in Scotland and Indian music mixing with jazz. So I wanted to bring all that together and reflect the vibrancy of all three styles that you can hear in Glasgow at the moment.”

Paul Towndrow’s Keywork Orchestra presents Deepening the River at the Merchants House of Glasgow on Friday August 10 and Saturday August 11.