Iskra String Quartet is a collaborative group of string players who enjoy making music together regardless of genre. Ivo Stankov (violin), James Underwood (violin), Sarah Chapman (viola), and Charlotte Eksteen (cello) have travelled extensively across Europe with Icelandic composer Jóhann Jóhannsson, performing at various prestigious concert halls and festivals, including "Different Trains: Steve Reich at 75" at the Barbican in London and Cork Opera House in Ireland. A highlight includes performances of The Miners' Hymns (2010), a collaboration with American artist and filmmaker Bill Morrison. Iskra has also enjoyed working closely with pianist and composer Ólafur Arnalds. A concert at the Queen Elizabeth Hall in London and a European tour led to an invitation to perform at the sold-out launch of Arnalds's 2013 album For Now I Am Winter (Mercury Classics) at the Barbican, accompanied by the Britten Sinfonia conducted by André de Ridder. The quartet's work with producer Jamie xx featured on the number-one best-selling album by The xx, Coexist (Young Turks, 2012). In 2015, Iskra contributed strings to Jamie xx's score for Tree of Codes, a ballet created with choreographer Wayne McGregor and visual artist Olafur Eliasson for the Manchester International Festival. Iskra's collaborations with composer Alex Baranowski have featured on the soundtrack to Jacqui and David Morris's 2012 two-time BAFTA-nominated film McCullin and in Sir Nicholas Hytner's production of Hamlet at the National Theatre in London starring Rory Kinnear. In 2007 Iskra were commissioned by Radiohead and XL Recordings to create a string quartet remix of Radiohead's "Reckoner" as part of the promotion of Radiohead's 2007 album In Rainbows. Other highlights include collaborations with artists such as Vampire Weekend, Sufjan Stevens, Benjamin Francis Leftwich, Katie Melua, Duke Special, My Brightest Diamond, and composers Dustin O'Halloran and David Julyan. In May 2015, Iskra performed as a trio alongside The Lone Bellow on the BBC Two TV show Later... with Jools Holland. Iskra includes compositions by Peter Gregson, David Julyan, Jóhann Jóhannsson, Alex Baranowski, Isobel Waller-Bridge, Ólafur Arnalds, Luke Anthony, and Paul Frith, and musical contributions from Gregson (cello), Baranowski (piano), and Christina McMaster (piano).