WHEN I speak with pianist William Howard, it is precisely 35 years to the day since the Schubert Ensemble of London gave their first recital at St Martin in the Fields in the heart of the capital. That detail is coincidental but nonetheless I expected him to have a ready answer to my first, obvious, question. Because the group’s current dates, which include six in Scotland, will be their last. Disarmingly – and charmingly – the co-founder of the quintet has no pat reply to trot out to justify calling it a day at this point.

“There’s no single answer,” he offers, a little hesitantly, “and no particular reason. None of us will be stopping playing. But we have all seen groups fizzle out, and after 35 years we wanted to end on a real high, while we were still enjoying it. It has to end sometime, and this is much better than waiting for someone to get ill.

“It is hard work sustaining an ensemble, and you are always looking four or five years ahead. Cutting down would just mean there being less of the enjoyable bit, which is playing. We plan to finish while we are still performing to a high standard and still, I think, improving all the time.”

Despite the group’s full title, The Schubert Ensemble of London, which accurately reflects its origins, it has always had a close relationship with Scotland, and appeared north of the border on a very regular basis. Cellist Jane Salmon was a member of the Scottish Chamber Orchestra for many years, and Howard knows the Borders well from regular family holidays at his grandmother’s home on the Tweed at Coldstream.

As well as playing concerts on tours of Scotland’s local music promoting clubs and societies over the years – and the final one begins with Perth Music Society on March 7 and also visits Biggar and Pollok House in Glasgow – the Schubert Ensemble has been resident ensemble at the Perth Festival of the Arts and at Orkney’s St Magnus Festival and performed at venerable chamber music venues in Scotland’s capital such as Greyfriar’s Kirk and the Queen’s Hall.

The reach of the group has been somewhat further than that, however. Bucharest, Tuscany and Luxembourg have featured on their recent European tour schedule, with visits across the Atlantic to Minnesota, Oregon and California – from where they return for the tour of Scotland. Past years have seen concerts in Nicaragua, Guatemala, Malaysia, Malta and Lebanon – the sort of travel that only an independently-minded ensemble could possibly have undertaken.

The current line-up also includes violinist Simon Blendis, Douglas Paterson on viola and bassist Peter Buckoke, another founder member but who will not be playing on the quartet of dates in Scotland. They have been playing together for 23 of the ensemble’s 35 years, and there has only been a single change in the group in the past 27 years. Just as crucially, they have been under the management of one dedicated person, Ann Senior, for three decades.

“We have never had an agent,” explains Howard of their relationship, “and Ann has been invaluable to the way the group has worked. No commercial agency would have taken on that role. She encouraged us to be adventurous.”

That has enabled what the pianist describes as “an independence of mind” in the projects the ensemble has undertaken, which encompasses some of their far-flung travels as well as education projects at home and abroad. Arguably the most significant aspect of their original thinking, however, has been the commissioning of new music. That process began “almost immediately”, says Howard, with the group premiering a new work by Colin Matthews in 1984, just a year after it was founded.

Like so much else in the Schubert Ensemble story, there is a pragmatic reason for the enthusiasm for new music. The quintet was formed to play the most famous work in the canon for that line-up of instruments: Franz Schubert’s “Trout” Quintet. A calling card from the start, Howard concedes that it quickly became a bit of a millstone. When the Schubert Ensemble played Edinburgh’s Queen’s Hall in March 2007 there was not a note of Schubert to be heard in a programme of Brahms, Suk and Chausson, and Scottish audiences will not be hearing music by the composer this year either.

“We formed to play the Trout at St Martins, and five years later we were already trying to break away from the association. We did feel a little saddled with the name back then, but there was also a certain safety net in that, and we have returned to the work since then.”

The key to that contentment has been building up other repertoire, and the ensemble has, Howard guesses, around 250 pieces to consider from its 35 years in active service. Of those, five are by Schubert, and five or six performances of the Trout Quintet each year seems only appropriate.

The huge amount of music the ensemble has commissioned includes a piano trio by Rory Boyle as well as pieces by Sally Beamish and Judith Weir, whose association with the group goes back to before its earliest days, Howard having commissioned her to write him a solo piano piece in 1981. She will be supplying their 50th major commission, a Song of Farewell, which will be premiered at London’s Wigmore Hall at the group’s official 35th Anniversary Concert on March 21.

The concerts leading up to that include, in America, The Whole Earth Dances by Cheryl Frances-Hoad, written for the quintet in 2016 and, on all the dates in Scotland, Charlotte Bray’s piano quartet Zustande, from 2017.

The representation of female voices in the group’s commissioning is pronounced but Howard refutes any suggestion of “trying to balance the books.”

“It is not a policy at all, we just invite people who work well with us. Cheryl and the ensemble go back a long way, while Charlotte we met through our residency at the Birmingham Conservatoire. We just choose the best composers.”

In fact both women also share an inspiration from the natural world, Charlotte Bray’s work following a visit to the glaciers of Greenland and Frances-Hoad’s drawing on the landscape poetry of Ted Hughes. Premiered at London’s Spitalfields Festival, it will appear on disc this year, while the Chausson Piano Quartet that will also feature in some of the Scottish concerts is on the ensemble’s latest Chandos label album.

The music the group is playing in its final months has been carefully chosen to balance new works with pieces they are returning to from earlier years, by Mozart, Dvorak and Faure, whose Piano Quartet No1 they play in Biggar and at both Glasgow concerts at Pollok House and Queen’s Cross Church.

“Going back to them for a final time is celebratory but emotional too,” says Howard.

He is looking forward to a mixture of re-focusing on his solo career and taking things a little easier. As well as solo recitals, he says there are “half a dozen concertos I would love to come back to.” Those include works by Schumann, Beethoven and Mozart “now I’ve grown up a bit.” His days of playing Brahms, Tchaikovsky and Rachmaninov are past now, he reckons.

“I’ll be 65 later this year and I will be able to do other things. I can’t afford to retire, but I am looking forward to working less intensively and being able to space things out in my own life. A slightly slower schedule will suit me well.”

The Schubert Ensemble play Perth on March 7, Biggar on March 8, Milngavie Music Club at Cairns Church on March 9, Stirling on March 10, Pollok House, Glasgow on March 11, and Aberdeen on March 12.