The government may be forced to amend its controversial new terrorism bill after a number of proposals were found to be in breach of human rights legislation.
A preliminary report by peers and MPs today finds new offences of encouragement of terrorism and attending terrorist training camps could be incompatible with the European Convention on Human Rights (ECHR).
The joint committee on human rights also questions plans to extend the time a terror suspect can be held in police custody without charge from its current limit of 14 days, saying it has yet to see evidence to justify this.
Today's report recognises the need for a new, narrowly defined criminal offence of indirect incitement to terrorist acts, but says it is concerned about the wording of the new offence of encouragement to cover this purpose.
Under current proposals, someone could be found guilty of encouraging terrorist behaviour regardless of whether they intended to do so - the only requirement is that the person hearing or reading their words or writings was encouraged.
Today's report calls for defences of "reasonable excuse" of "public interest" be included in the legislation, to reduce the chance of prosecutions being thrown out of court as being incompatible with the ECHR.
Equally, it calls for their inclusion in the new offence of training for terrorism. Academics and journalists fear it they could be found guilty of terrorism in the course of legitimate research, even if their purpose there was in the public interest.
These recommendations will be welcomed by opposition parties, Labour backbenchers and civil rights campaigners, who have long argued for the element of intent to be included in the terrorism proposals.
The committee's views on detention of terror suspects will also make good reading for critics, as it finds that it has yet to see evidence to justify the time terrorist suspects can be held without charge.
Last month, MPs rejected government plans to extend the detention limit to 90 days, and today's report finds that this would have been "clearly disproportionate" and accompanied by "insufficient guarantees against arbitrariness".
Instead, the Commons voted for a compromise detention period of 28 days, but the committee raises concerns about this too, saying that case has yet to be made for an increase from the current 14-day limit.
However, it does not rule out the possibility that evidence justifying this increase could be made, in which case extending the detention time would be proportionate, subject to certain safeguards.
The committee welcomes the government's insistence that detention would be subject to the scrutiny of a high court judge, but says the Terrorism Act 2000 must be amended to allow suspects to consult a lawyer during that period.
In addition, it recommends "nothing less than a full adversarial hearing before a judge" when deciding if further detention is required, and that a higher level of police officer be responsible for the application.
"The presumption should be in favour of liberty, not detention," the report adds.
Finally, it looks at the government's use of memoranda of understanding with other countries to ensure that anyone deported on the grounds of national security would not be tortured in the destination country.
Campaigners have warned of the validity of these agreements, which have so far been signed with Libya and Jordan, but today's report says they are "capable, in principle, of satisfying the state's obligation [under ECHR] not to return an individual to a serious risk of torture".