Why are Hollywood actors and writers on strike?

Hollywood's actors and writers will join forces on the picket line from Friday, after studios failed to reach a deal this week with the Screen Actors Guild – American Federation of Television and Radio Artists (SAG-AFTRA). It is the first time the two unions have been on strike simultaneously since 1960, when actor – and future US president – Ronald Reagan led the protests. Among SAG-AFTRA's 160,000-strong ranks are many of the world's biggest stars. Hollywood's A-listers, from Tom Cruise to Angelina Jolie to Johnny Depp, are card-carrying union members. Stars including Meryl Streep, Ben Stiller and Colin Farrell have come out publicly in favour of the strike.