Actor Benedict Cumberbatch stunned onlookers on the set of Sherlock on Wednesday (21Aug13) by staging a bizarre one-man protest against government measures to silence whistleblowers in the wake of the WikiLeaks scandal.

The issue of free speech erupted in the U.K. this week (beg19Aug13) after it emerged cops used anti-terror laws to detain and question the partner of a journalist at an airport.

Officials quizzed David Miranda because his partner was involved in exposing mass surveillance by the U.S. and U.K. governments revealed by former Cia computer specialist Edward Snowden.

Now Cumberbatch has waded in to the issue by staging the odd protest, during which he held up a series of handwritten messages for photographers on the set of the Tv detective drama.

Wearing dark glasses and a smart suit, he held aloft the notes which made reference to Schedule 7 of the U.K.'s Terrorism Act - which gives police the power to stop and search passengers at airports - and allegations government officials supervised the destruction of a computer hard drive containing Snowden's allegations.

Cumberbatch's notes stated, "Hard drive smashed, journalists detained at airports... Democracy? Schedule 7 prior restraint. Is this erosion of civil liberties winning the war on terror? What do they not want you to know? And how did they get to know it? Does the exposure of their techniques cause a threat to our security or does it just cause them embarrassment?"

Snowden, who exposed mass surveillance of U.S. and U.K. citizens by their own governments, is currently in hiding in Russia. WikiLeaks founder Julian Assange, who Cumberbatch portrays in a new movie biopic, is living at the Ecuadorian embassy in London as he fights extradition to the U.S. after publishing thousands of leaked confidential military documents on the website.