One of the most valuable functions of the Booker Prize is to truffle out those novels published by small independent firms that are of high quality but rather less classifiable – and marketable – than the offerings of mainstream publishers. The well-deserved longlisting of Siân Hughes’s debut novel, Pearl, will grant it a level of attention that Indigo Press could otherwise only have dreamed of. Pearl is a slow-burning meditation on grief and memory, determinedly low-key, fuller of reflection than incident, and using its language with precision rather than floweriness. It’s narrated by Marianne, a single mother in her 30s whose life has been haunted by the sudden disappearance of her mother, Margaret, when she was eight.…