HMRC has lost a disc containing personal information on Standard Life customers who are contracted out of the state second pension.
Standard Life is pulling out all the stops in its bid to snatch Resolution from the rival Pearl Group.
Pearl has continued its assault on Standard Life, claiming it has launched a "dilutive, value destructive bid".
Pearl Group has called on Standard Life to show its hand after announcing it will block the insurer's current offer for Resolution.
The Takeover Panel has reportedly reprimanded Standard Life for breaching takeover rules in its announcements regarding a possible offer for Resolution.
The Hugh Osmond led Pearl Group is having "difficulty understanding" why Resolution has not recommended its cash offer to shareholders.
Standard Life may change the structure of its Resolution takeover to thwart moves by Pearl, which now owns 24% of the target.
Standard Life's sales through channels other than IFAs rose to 41% in the third quarter up from 26% in 2006, according to the group's interim results.
Pearl has launched a late fightback to assume control of Resolution, tabling a 720p per share offer.
The Resolution board has unanimously recommended the Standard Life takeover offer, ending its proposed merger with Friends Provident.