Prime Minister David Cameron, defending his integrity to parliament in emergency session Wednesday, said he regretted hiring a journalist at the heart of a scandal that has rocked Britain's press, police and politics. But in hours of stormy questioning he seemed to rally his Conservative party behind him and stopped short of bowing to demands that he apologize outright for what the Labour leader called a “catastrophic error of judgment” in appointing as his spokesman a former editor of Rupert Murdoch's News of the World. Only if Andy Coulson, who has since resigned, should turn out to have lied about not knowing of illegal practices at his newspaper would the prime minister offer a “profound apology”. After his toughest two weeks in office, the 44-year-old premier spoke with feeling of the Coulson saga: “You live and you learn – and believe you me, I have learnt,” he said. “It was my decision ... Of course I regret and I am extremely sorry about the furor it has caused. With 20:20 hindsight ... I would not have offered him the job.” He said of Coulson, who is under suspicion of conspiring to intercept calls and bribe police: “I have an old-fashioned view about innocent until proven guilty. But if it turns out I have been lied to, that would be a moment for a profound apology. “And, in that event, I can tell you I will not fall short.” Beleaguered but hardly under serious threat of being ousted by his party allies after less than 15 months in power, Cameron defended his actions and those of his staff in dealings with Murdoch's News Corp global media empire and with two senior police chiefs who resigned this week over the affair. “He seems to have gained a bit of breathing space over the course of this debate,” said Andrew Russell, senior politics lecturer at Manchester University. “He looked more self assured today than he has been for a little while.” Conservative member of parliament George Eustice spoke for a party relieved by the leader's performance: “Cameron did really well. He's got back on the front foot and taken the initiative.”