The New York Times reports:

The phone hacking scandal in Britain claimed another high-profile casualty on Monday when John Yates, the assistant commissioner of the Metropolitan Police in London, resigned his post. His departure comes a day after the country’s top police officer quit and Rebekah Brooks, the former chief executive of Rupert Murdoch’s News International, was arrested on suspicion of illegally intercepting phone calls and bribing the police.

Such is the severity of the crisis swirling around the Murdoch empire and Britain’s public life that Prime Minister David Cameron cut short an African trip on Monday and, bowing to opposition pressure, called a special parliamentary session on Wednesday to debate the widening scandal.

Mr. Yates is a well-known officer who had been involved in an earlier and inconclusive police review of the scandal. He and other officers have been under scrutiny by lawmakers who are trying to determine why the Metropolitan Police decided in 2009 to strictly limit the initial phone-hacking inquiry, dating to 2006.

Shortly after the Metropolitan Police announced his resignation, Mr. Yates made a defiant public statement: “I have acted with complete integrity,” he said. “My conscience is clear.”

Kiran Stacey notes that the resignation of Met Commisioner, Sir Paul Stephenson, puts the British prime minister in an even tighter corner. If Stephenson had to resign for appointing Neil Wallis, shouldn’t Cameron resign for appointing Andy Coulson?

Sir Paul Stephenson’s resignation yesterday was a significant moment in the phone hacking affair: not only because of the fact of his resigning but because of what he said afterwards.

He made two subtle but important criticisms of the prime minister:

1) He said he had resigned in part for having employed Neil Wallis, the former deputy editor of the News of the World, who has since been arrested, but did not have to resign from the NotW for his part in the scandal. He compared this to Andy Coulson, who had been forced to resign, but was also given subsequent employment – by the prime minister.

2) Sir Paul also said he did not want to “compromise the prime minister” by telling him about Wallis’ involvement either with the Met or the fact that he was a suspect in the hacking affair, given Cameron’s “close relationship with Mr Coulson”. This came close to, without doing so directly, saying that Cameron could not have been trusted with such information, and may have jeopardised the operation (or at least been accused of jeopardising it) by telling Coulson. It’s an extraordinary claim, which [Labour MP and shadow Home Secretary] Yvette Cooper was quick to highlight…