The legislation is due to be extended to cover private companies carrying out public services. Brown also announced that the power of the police to stop protesters around Parliament is to be reviewed.
The future of the peace camp started by protester Brian Haw on Parliament Square is also to be considered. Brown said the square must be protected as a World Heritage Site.
Section 44 of the 2000 Terrorism Act, which gave the police the power to arrest protesters such as Walter Wolfgang, the veteran radical who was famously evicted from the 2005 Labour Party Conference for heckling, is also to be reviewed after an outcry at alleged police abuses.
Calling for “a new chapter in our country’s story of liberty”, Brown pledged that the changes would include “new rights for the public expression of dissent”.
Shami Chakrabarti, director of civil rights organisation Liberty, said: “After so many years of relentless political attacks on liberty, it is brave for any Prime Minister to give a speech in its name.
“He must be aware, however, that this does not sit well with detention without charge and compulsory identity cards. The standards, like the stakes, must now be raised.”
Katie Ghose, director of the British Institute of Human Rights, also gave the announcement a cautious welcome.
“The Prime Minister has shown leadership in his rediscovery of the true value of liberty and human rights for people in Britain. But there must be no backsliding from this restored commitment to human rights. Only a cast-iron guarantee that the Government’s reforms will build on the rights we already have in the Human Rights Act will reassure us of the Prime Minister’s good intentions.”