Anyone who thinks ‘classical music’ equals ‘serious’ should give the Oxford Concert Party a try.

Forget any ideas of stuffiness or pretentiousness; these unconventional, down-to-earth musicians give classical music a refreshing new twist, infusing their concerts with humour and vitality.

The unusual pairing of baroque and tango also makes them stand out from the crowd, and indeed they bill themselves as ‘Europe’s only baroque and tango orchestra’.

The group was started by Arne Richards and Isabel Knowland, who began playing together on the harpsichord and violin respectively, and decided to expand to a string quintet with harpsichord or accordion accompaniment. Twenty years on, they are amazed to find themselves still going strong.

“We’ve always got on very well together as a group,” says Arne. “It’s very rare for a group to playing together this long, and still be speaking to each other!”

“We are really good friends,” agrees Isabel. “Partly I think that’s because of the music itself, but also because our intention was very definitely to have fun playing.

“I come from a strictly orchestral training background, where there is a certain rigidity and certain conventions, where you don’t get the chance to express yourself as a player. So we wanted to give people the opportunity to be themselves.”

Behind the fun, though, there are serious intentions. Arne is a trained Music Therapist, and much of the group’s focus over the years has been on projects in schools, prisons and day centres for the elderly.

“It was always Arne’s idea that this has to be do with healing,” says Isabel. “Also there was a shared ethos that we wanted to break down conventional barriers and make music more accessible. So partly that’s the reason for going into prisons and working with older people — people who wouldn’t normally have an opportunity to hear live music.” The 20th anniversary concert will feature a selection of pieces, old and new, all reflecting the group’s extraordinarily diverse repertoire, from baroque to Celtic, from European music to tangos and waltzes from Central America.

Expect to hear music by Purcell and Piazzolla, Irish composer O’Carolan and Scottish composer J. Scott Skinner, as well as original compositions and arrangements by Arne.

The concert will also see the launch of a new CD, recorded live in Oxford last autumn, as well as a cookbook, featuring some of the group’s favourite recipes from when they are on tour together.

“I hope it’s going to be a fun book, but also give a flavour of what we’ve done over the years, as well as the fact that we’ve enjoyed each other’s company, because that’s been very much of it,” explains Isabel. “If you can relax and have fun together, it makes working conditions easy.

“We have done a lot of travelling, combining concerts with community projects, and it’s very fulfilling to do that mixture. I feel very privileged. We have been very lucky, and it really is something to celebrate.”

The Oxford Concert Party 20th anniversary concert is at the Holywell Music Room on Friday, April 13. Call the box office on 01865 305305 or visit ticketsoxford