A former head of MI5 believes French authorities were blamed too quickly for the Paris terror attacks.
Baroness Eliza Manningham-Buller also said the hunt for scapegoats was damaging and that no service is automatically at fault when something like last November's tragedy occurs.
However she added that she was not seeking to suspend accountability and that she would have resigned if MI5 was found to have made a serious error under her leadership.
Baroness Manningham-Buller told the Radio Times: "The head of a Commonwealth security service once told me he intended to resign if a terrorist act happened under his watch, but it's a mistake to assume that a service is automatically at fault when that happens.
"Remember the statement by the Provisional IRA after the Brighton bombing - 'We have only to be lucky once. You will have to be lucky always'.
"The hunt for a scapegoat (an individual or an organisation) is damaging. It leads to a reluctance to experiment or innovate. We don't make progress unless we do."
She also highlighted that if people are frightened of being blamed at work, their judgment may be affected as well as their morale.
"We should not kid ourselves that by making more rules, passing new laws and blaming people indiscriminately we will catch every criminal, put a stop to terrorism and make our world completely safe," said Baroness Manningham-Buller whose remarks will feature in The Blame Game this Sunday on BBC Radio 4.
The full interview is in this week's Radio Times.