The Director General of MI5 has defended the security services right to remain secret in the wake of the Edward Snowden NSA and GCHQ leaks.
Speaking in public for the first time since taking on the role Andrew Parker said publishing details of the service's work, "hands the advantage to the terrorists."
He said: "What we know about the terrorists, and the detail of the capabilities we use against them together represent our margin of advantage. That margin gives us the prospect of being able to detect their plots and stop them.
"But that margin is under attack. We are facing an international threat and GCHQ provides many of the intelligence leads upon which we rely.
"It makes a vital contribution to most of our high priority investigations. It causes enormous damage to make public the reach and limits of GCHQ techniques.
"Such information hands the advantage to the terrorists. It is the gift they need to evade us and strike at will. Unfashionable as it might seem, that is why we must keep secrets secret, and why not doing so causes such harm."
David Cameron is expected to urge all G8 leaders to commit their countries not to pay terror ransoms in an international effort to cut off extremists' funding.
Up to 70 million US dollars (£45 million) is estimated to have been paid to secure the release of Western captives in the last three years alone - an average 2.5 million US dollars (£1.59 million) per victim.
Much of that is believed to have ended up in the coffers of terror groups including al Qaida and its affiliates and the Taliban.
The UK outlaws such payments but other countries - including some within the group of leading industrialised nations - continue to meet the demands to the frustration of non-payers.
The Luton terrorist group were trying to make an an improvised explosive device (IED) based on instructions in an al Qaida manual entitled "Make a bomb in the kitchen of your mom - by the al Qaida chef", the court was told.
Covert recordings of the pair heard Iqbal suggesting attaching the bomb to a remote controlled toy car and sending it under the gap of a gate to a Territorial Army (TA) centre in Luton.
The men were arrested following a series of raids at their homes in April last year after an intelligence-led joint operation by the Metropolitan Police Counter Terrorism Command and the British Security Service (BSS).
A Territirial Army centre in Luton was the planned target for a terror group. Four men have admitted engaging in conduct in preparation for acts of terrorism.
Four Luton men could be sentenced today after admitting discussing carrying out a terror attack in the UK.
Zahid Iqbal, 31, Mohammed Sharfaraz Ahmed, 25, Umar Arshad, 24, and Syed Farhan Hussain, 21, considered methods, materials and targets for an attack.
The men were arrested following a series of raids in April last year. They pleaded guilty to one terrorism charge at Woolwich Crown Court.
The four men downloaded computer files containing practical instruction for an attack, and collected funds for terrorist purposes.
They also admitted facilitating, planning and encouraging travel overseas, as well as organising, encouraging and participating in physical training, contrary to section 5 of the Terrorist Act 2006.
The offences took place between January 2011 and April last year.
Irfan Naseer, 31, and Irfan Khalid, 27, travelled to Pakistan for terrorist training before returning to the UK in July last year, jurors at Woolwich Crown Court were told.
In one conversation, Naseer was heard agreeing that the July 7 attacks had not done enough damage because there were no nails in the bombs.
The two men, along with Ashik Ali, also 27, are accused of being "central figures" in the alleged extremist plot.
Ali told police in interview that the plan had involved him wearing a suicide vest as well as carrying a gun, the jury heard.
Radical cleric Abu Hamza has pleaded not guilty in a New York court to charges he conspired to set up a terrorist training camp in the US, according to the Associated Press.
The wife of Abu Hamza has been asked to move out of her five-bedroom council house in west London. Najat Mostafa has reportedly been living at the property in Shepherd's Bush since 1995. But Hammersmith and Fulham Council wants her to move to a smaller home.
We believe this home is too big for the number of family members who currently live there and, with over 10,000 people languishing on the borough's housing waiting list, she should move to a more appropriate property.
Najat Mostafa is allowed to refuse the council's request because there is no time limit on her tenancy agreement.
Abu Hamza was in custody in New York today awaiting trial on charges of bombing two United States embassies in Africa.Read the full story ›