'I'm all feathered out' – why mas is the heart of Notting Hill carnival

With its dancers, devils and elaborate handmade costumes, mas - short for masquerade - is carnival's oldest tradition. We meet the women keeping it alive

In a workroom in the Yaa Centre in west London, surrounded by bolts of fabric and sewing machines, Allyson Williams is reminiscing about her first mas camp. For the uninitiated, mas camps are where carnival bands gather to make their costumes by hand. Now 72, the former midwife - she was awarded an MBE for her services in 2002 - smiles broadly at the memory. "It was wonderful. I thought, oh my God! This is like home."

For the Williamses, mas is a family business. It started with Allyson's husband, Vernon, who came to London in 1956. As a Trinidadian, like Allyson, carnival was in his blood. After meeting his wife-to-be in 1975, Vernon wasted no time in introducing her to Notting Hill Carnival, which he had co-founded in 1966.