News Corporation chief Rupert Murdoch has further criticised former legal adviser Harbottle & Lewis in his testimony to the Leveson Inquiry, which also saw him lay blame on former News of the World legal manager Tom Crone for his role in an alleged phone-hacking 'cover-up'.

In reference to Harbottle's role advising the company during a 2007 investigation into phone-hacking at News International, Murdoch said today (26 April) that he could not understand a law firm reading the emails they were given and "not ringing the chief executive of a company and saying, 'Hey, you've got some big problems'."

His criticism came after he gave an interview to The Wall Street Journal last July in which he said Harbottle had made "a major mistake" in its part in the investigation.

During the questioning by Lord Justice Leveson and Robert Jay QC today, Murdoch claimed that he and other senior executives had been shielded from what was really going on at the News of the World, laying blame for a cover-up on his editors and lawyers.

While he did not directly name Crone it was apparent he was referring to him and at one point he suggested the company had made a mistake by allowing Crone to serve for so long, stating: "I think we should not have allowed – not have had one legal officer at the News of the World for 20 years. I think those sort of people should be changed every five or, at the worst, every 10 years."

In response, Crone later put out a statement saying: "Since Rupert Murdoch's evidence today about a lawyer who had been on the News of the World for many years can only refer to me, I am issuing the following statement.

"His assertion that I 'took charge of a cover-up' in relation to phone-hacking is a shameful lie. The same applies to his assertions that I misinformed senior executives about what was going on and that I forbade people from reporting to Rebekah Brooks or to James Murdoch.

"It is perhaps no coincidence that the two people he has identified in relation to his cover-up allegations are the same two people who pointed out that his son's evidence to the Parliamentary Select Committee last year was inaccurate."

The testimony also saw Murdoch state News Corporation had spent hundreds of millions of dollars on the hacking scandal, examining 300 million emails during its internal investigations, with Linklaters reviewing two million of these on behalf of News Corp.

The session also saw Murdoch questioned about why News International had not waived client privilege for criminal law firm BCL Burton Copeland, which was "heavily involved" in the phone-hacking investigation in 2007 alongside Harbottle. BCL's report has not been seen and the firm has not been able to provide testimony to the inquiry due to client privilege.

Additionally Murdoch said he was "shocked" by The Times' former legal manager Alastair Brett "not telling (Mr Justice Eady) the truth of a lot of things".

Brett came under scrutiny at Leveson last month after he conceded that statements submitted to the High Court in 2009 regarding the 'Nightjack' case – which saw anonymous police blogger Richard Horton attempt to obtain a High Court injunction to prevent a reporter at The Times identifying him – were "not entirely accurate", after it emerged that the reporter in question, Patrick Foster, had uncovered Horton's identity through email hacking.