The former head of MI5 has accused the government in an interview of eroding civil liberties by exploiting fears over terrorism.

Dame Stella Rimington said interfering with people's privacy played straight into the hands of terrorists.

She told Spanish newspaper La Vanguardia the clampdown risked creating a "police state".

"It would be better that the government recognise that there are risks, rather than frightening people in order to be able to pass laws which restrict civil liberties," she said.

"(That is) precisely one of the objects of terrorism: that we live in fear and under a police state," she added.

Dame Rimington, 73, also criticised the approach of the United States to fighting terrorism.

"The US has gone too far with Guantanamo and the tortures. MI5 does not do that. Furthermore, it has achieved the opposite effect: there are more and more suicide terrorists finding a greater justification," she said.

Dame Rimington said the British secret services were "no angels" but insisted they did not kill people.

She became the first woman director general of MI5 in 1992 and was head of the security agency until 1996.

Since stepping down, she has been critical of the government's counter-terrorism and security measures, especially those encroaching on civil liberties.

Last year, she called attempts to extend the period of detention without charge for terrorism suspects to 42 days excessive, shortly before the plan was rejected by Parliament.

She has also attacked the government's controversial plans to introduce ID cards, saying they would not make the public any safer.