The absence of black actors among the nominees for the Oscars - for the second year running - is "unforgivable", says British actor David Oyelowo.

Oyelowo was overlooked last year for his performance as Martin Luther King in Selma.

There are calls to boycott this years Oscars ceremony, and the director Spike Lee has already said he will not be attending.

The Academy of Motion Picture Arts and Sciences has said it is looking again at the diversity of its membership, as James Cook reports.