"The only thing stopping that is cost," said Sir William. "But whether it happens in one year or five, it will certainly happen."
Framestore was responsible for a chocolate bar TV advertisement that featured a digital recreation of the actress Audrey Hepburn, after approval was sought from her two sons. "It was a high-risk venture because they could have stopped it at any time," said Sir William.
"We can recreate dead actors," said Mike McGee, Framestore's co-founder.
"Actors alive now are selling their image rights for films that will be made when they're dead. In their will, they have to decide what constraints they want for that."
The technological barriers preventing the digital recreation of a person so perfect as to be undetectable to another human have been crossed in the last couple of years, according to Tim Webber, the effects superviser on Gravity.
"The actual world and the imagined world are coming together," he said. "Visual effects have merged with the real."
That poses ethical questions that the team at Framestore - founded in 1986 - never imagined they would encounter.
"I worry about the JFK example. There are so many sensitivities. You have to balance educational benefits against the wishes of friends and family."