Britain's anti-terror laws are in danger of catching journalists, bloggers and other people they were never intended to cover, the independent reviewer of terrorism legislation has warned.
David Anderson QC said the legal definition of terrorism was too widely drawn and called on Parliament to revisit the legislation.
"The problem is that our definition has begun to catch people that it was never really intended to catch," Mr Anderson told the BBC Radio 4 Today programme.
"I give credit to the prosecuting authorities and to the police and indeed to ministers because I don't think they very often abuse or stretch the very wide discretions they are given under the Act.
"The problem is more that people who should never get caught by these laws just get worried that they might be and that could have the effect of restricting the way that they go about their business."
Mr Anderson, who publishes his annual report today, warned that the public would only continue to accept the legislation - which gives the authorities extended powers of arrest and detention - if they were sure it was genuinely needed.
"You could look at the example of journalists and bloggers, for example, who can be considered terrorists, it seems, if they are seeking to influence the Government and if their words endanger life or create a serious risk to public health or safety. Foolish or dangerous journalism is one thing, terrorism is another," he said.
"I think the problem there is the way the bar is set. It is enough that you are trying to influence the Government for political reasons. In most other countries you need to have to intimidate the government or coerce the government before you can be a terrorist."
He referred to the case of David Miranda - the partner of journalist Glenn Greenwald who was involved in publicising the disclosures of former US intelligence contractor Edward Snowden - who was detained at Heathrow Airport for several hours on suspicion that he was carrying stolen documents.
"I would certainly accept that the police ought to have the power in those circumstances to stop somebody and detain them and see what's going on. What I think is more difficult to defend is the use of anti-terrorism laws for that purpose," Mr Anderson said.