Private detective Glenn Mulcaire has revealed the names of News of the World staff who instructed him to carry out phone hacking, his solicitor has confirmed.
The information was passed in a letter to comedian Steve Coogan's lawyers in accordance with a court order.
Mulcaire had applied for permission to appeal against the order, which was made in February, but this was denied and he was compelled to pass over the details by Friday.
His solicitor Sarah Webb, from Payne Hicks Beach, said she could not reveal who the NOTW employees were because of "confidentiality issues".
Schillings, which is representing Coogan, has agreed not to reveal the names yet, to give Payne Hicks Beach a chance to apply for a court order stopping their release.
Mulcaire was ordered to reveal who instructed him to access Coogan's voicemails, as well as those of celebrities including PR guru Max Clifford and model Elle Macpherson.
He was jailed for six months in 2007 for intercepting messages left on royal aides' phones.
A spokeswoman for News International said the firm had no comment.