LONDON — The official who oversaw the much-criticized initial police inquiry into Britain's phone hacking scandal said Thursday that a crush of terrorism cases meant his force had no choice but to curtail its media investigation.

Former Scotland Yard counterterrorism chief Peter Clarke testified that police were so badly stretched by the threat of al-Qaida attacks in 2005 it had to enlist 1,000 officers from other bodies. In that context, the investigation into phone hacking had to take the back seat.

"Invasions of privacy are odious, and sometimes illegal, but to put it bluntly they don't kill you," he said. "Terrorists do."

The London transit system was hit by terror attacks in 2005 that killed 52 commuters.

Clarke spoke at Britain's official inquiry into media ethics, a body set up by Prime Minister David Cameron after the unveiling of widespread phone hacking at Rupert Murdoch's News of the World tabloid, which spent years breaking into the phones of prominent people to get front-page scoops. Murdoch shut down the tabloid in July after advertisers and readers were outraged.

The initial U.K. police investigation into the phone hacking scandal uncovered thousands of pages of evidence suggesting that several senior journalists at the now-defunct tabloid had ordered private detective Glenn Mulcaire to hack into phones of hundreds of victims. Those victims included members of the royal household, the then-Deputy Prime Minister John Prescott, and other high-level figures.

But Scotland Yard failed to follow leads, interview suspects or notify victims, closing its investigation with the conviction of Mulcaire and only a single journalist: The News of the World's royal correspondent, Clive Goodman.

Clarke said part of the problem was that Murdoch's News International, the paper's publisher, had stonewalled investigators. Clarke pushed back against allegations that his police force had helped Murdoch's company cover up its crimes.

But he acknowledged overlooking details "which, with hindsight, were very important."

Clarke said, given the huge number of terror cases which the force was dealing, with he stood by his decision not to pursue the initial investigation any further.

"I haven't seen anything that would cause me to take a different decision than I took then," he said.

Online:

The official inquiry: http://www.levesoninquiry.org.uk/

Raphael Satter can be reached at: http://twitter.com/razhael