Alan Yentob follows the celebrated Turner Prize-winning British artist Chris Ofili as he creates a spectacular contemporary tapestry - The Caged Bird's Song. Nearly three years in the making, it is a triumph of craft and dedication, transforming Ofili's free-flowing watercolour paintings into vibrant wool on a giant scale. Made with a team of master weavers in Edinburgh, the piece, over seven metres wide and three metres tall, draws together the sights and sounds of tropical Trinidad, where Ofili lives. Imagine explores Ofili's passion for his adopted island home and its inspiration on his creative practice, and reveals the final tapestry as it is installed in an exhibition at the National Gallery in London.