An inquiry into the illegal interception of cell phone voicemail messages by a private investigator working for the News of the World has hit headlines after it emerged families of murder victims and those affected by the 2005 London Underground bombings may have been targeted.
But the Notting Hill star admits he's "panicking" that government officials conducting the probe into the print media will fail to examine the power newspaper bosses hold over politicians.
He tells The Guardian, "I'm panicking that despite all the revelations coming out thick and fast, the government, with their history of collusion and obedience to (News of the World publisher) News International, will find a way to make this inquiry insufficient and kick it into the long grass.
"Grotesque abuses have been allowed to continue because of the cowardice of our politicians, who have done pretty much... what they've been told to, partly because they believe News International can get them elected and partly because of a kind of blackmail. There has been a grotesque power over our lawmakers."
Now the actor is challenging Cameron to demand a thorough review of the entire industry, adding: "This is a watershed moment for David Cameron and his government. He can either continue to be (media mogul Rupert) Murdoch's little helper or he can be a statesman. If it's the latter, he needs to announce a wider inquiry. It must cover the press, police and politicians."