Ivor Novello Award nominiee Jess Glynne brought a splash of colour to the red carpet as she arrived in a jazzy ensemble teamed with circular sunglasses.
The singer was nominated for the PRS for Music Most Performed Work award.
She was beaten to the gong by James Bay for his song Hold Back The River, the second track from his debut album Chaos And The Calm.
Accepting the award, which goes to the most played song in the UK in 2015, he said that he "definitely didn't expect to win".
Meanwhile, Ed Sheeran will go head-to-head with his protege Jamie Lawson at the awards.
Jamie, who was the first artist signed to Sheeran's record label, Gingerbread Man Records, is in the running for Best Song Musically and Lyrically for Wasn't Expecting That, a re-release of his first single from 2011 that peaked at six in the charts last year.
The 40-year-old goes up against his mentor Ed and Rudimental for their collaboration Bloodstream at the ceremony, with Wolf Alice's Bros completing the nominations for that category.
Snow Patrol band mates Johnny McDaid and Gary Lightbody are nominated as co-writers on Bloodstream and rumours that Johnny had reunited with his ex-fiancee, Friends star Courteney Cox, were supported by her attendance at the awards, although she arrived separately from the band.
Presented by the British Academy of Songwriters, Composers and Authors (Basca), the awards celebrate excellence in songwriting and composing and are highly respected because they are voted for by industry members.
Supergrass lead vocalist Gaz Coombes goes up against Irish indie folk band Villagers and Jamie XX for the album award.
The ceremony is taking place at London's Grosvenor House.