A top Scotland Yard officer is due to appear before MPs amid claims that he misled parliament over the phone hacking scandal.
Acting Deputy Commissioner John Yates was accused of conspiring with the News of the World when the allegations were investigated by the Metropolitan Police.
He will be quizzed by the Culture, Media and Sport Select Committee after he asked for the opportunity to "rebut" the claims of Labour MP Chris Bryant.
In a letter to committee chairman John Whittingdale, Mr Yates said the MP had made "very serious allegations" about his integrity.
"I am most concerned that the reputation of the Metropolitan Police as well as my own is being damaged by these unfounded allegations," he said.
"You may therefore think it sensible that I be provided with the opportunity to allay Mr Bryant's, and perhaps your, concerns."
Mr Bryant, MP for Rhondda, told the Commons this month that the officer had misled the Home Affairs Select Committee last September by claiming there were only eight to 12 phone hacking victims by News of the World journalists.
He claimed at least eight MPs were among the victims and said executives at the News of World met senior officers during the original investigation and when there were calls for it to be re-opened.
A dinner in 2009 between then Assistant Commissioner Yates and News of the World editor Colin Myler happened just as the officer was refusing calls to reopen the investigation, he claimed.
The meeting was "at best ill-advised or at worst fairly or unfairly smacks of collusion", Mr Bryant told MPs.