Labour anxiety and accusations after big shift in Muslim vote to Greens

PM criticises sectarian politics' in byelection but party may fear Greens' nascent leftwing political machine

The Green party's success at winning Muslim votes in Gorton and Denton has sent tremors through Westminster, prompting recriminations and accusations from opposition parties, who sense another major realignment in British politics.

Experts say Hannah Spencer's unexpectedly wide margin of victory was delivered in part by a significant shift of Muslim voters from Labour to the Greens.