Lawyers for firm contracted to NI said it deleted emails on nine occasions since May 2010: there was 'nothing abnormal'

Senior MPs want to question further one of News International's technology suppliers, after the firm responsible for overseeing its day-to-day emails revealed that hundreds of thousands of them had been deleted on a total of nine occasions from the newspaper publisher's server since May last year.

Lawyers acting for HCL, the firm contracted to oversee News International's email system, told the home affairs select committee that it was aware of "nothing which appeared abnormal, untoward or inconsistent with its contractual role" – but went onto to advise MPs to direct further questions to News International.

The law firm, Stuart Benson, acting for HCL, said: "It is entirely for News International, the police and your committee as to whether there was any other agenda or subtext when issues of deletion arose and that is a matter on which my client cannot comment and something you will no doubt wish to explore direct with News International."

Keith Vaz, chair of the committee, said he was most surprised by the deletions and added that the MPs would be seeking further details from HCL, the firm contracted to oversee the News International's 'live emails', typically those less than 15 days old.

Meanwhile, Labour MP Chris Bryant, an active campaigner against phone hacking, said: "All these dubious deletions prove yet again how much better it would have been if the Metropolitan Police secured the whole system back in 2006.

"It certainly looks as if, in the words of one Metropolitan Police officer to the Commons culture select committee, that News International were deliberately thwarting their investigation."

HCL said it had been aware of discussions around at minimum nine separate episodes of email deletions – part of the internal company archive which the Met are using to examine the extent of phone hacking at the News of the World.

HCL's lawyers also noted that a second unnamed supplier had been responsible for emails more than a couple of weeks old, and at times HCL had co-operated with this vendor in deleting material.

HCL identified three sets of email deletions in April 2010, including a deletion of a public folder of a live email system that "was owned by a user who no longer needed the emails". A further 200,000 emails "stuck in an outbox" were deleted in May 2010 to restore email functionality. In September 2010 a further pruning of historic emails occurred to help stabilise the email archival system, which had been having "frequent outages" since November 2009.

In January 2011, HCL was asked about its ability to "truncate" a particular database in the email archival systems. HCL "answered in the negative and suggested assistance from the third party vendor".

In February 2011, emails were deleted in an older version of the software. Finally, in July 2011 HCL deleted emails from the live system as "relocation errors" had occurred when the systems were moved.

News International sources indicated that the email deletions were part of sensible housekeeping of an email system that had been unstable, and at one point had gone down for three days. The company says it has a good working relationship with police investigating the hacking crisis, although last month it emerged that Scotland Yard investigators were unhappy about the scale of the deletions.

Separately, a firm of solicitors drawn into the News International phone-hacking scandal is expected to reply shortly to the home affairs select committee as to how it came to write a key letter to the newspaper group that was then used by the company to contend that phone hacking had not been widespread at News of the World.

The firm, Harbottle and Lewis, is consulting the Metropolitan police before deciding how to reply to requests from the select committee to spell out how it came to write a letter taken to mean that only one reporter was aware of phone hacking at the paper.

The New York Times reported at the weekend that the letter sent by Harbottle and Lewis to the culture, media and sport select committee was redrafted more than once. The firm had been hired to review the email of the tabloid's royal reporter, Clive Goodman, who had pleaded guilty to hacking the mobile phone messages of royal household staff members. The letter said "no reasonable evidence" had been found that senior editors knew about the reporter's "illegal actions".

A News International spokesman said: "NI keeps back-ups of its core systems and, in close co-operation with the Operation Weeting team, has been working to restore these back-ups."