Pressure is building on Lloyds Banking Group to acknowledge that it is at the centre of an important inquiry into complaints of maltreatment.

This could result in having to assess tens of thousands of complaints that it has formerly discarded and could lead to a sizeable penalty.

Lloyds name was not openly mentioned in a derogatory report that was published last week by the Financial Services Authority on the issue of poor complaints-handling by banks.

But it appears to have been recognized by the FSA as one of two banks where consumers' complaints were methodically treated unjustly.

This could imply that tens of thousands of complaints to the bank were accidentally dismissed or poorly rewarded.

Lloyds declines to verify if it is or not one of the two culprits. It says that it 'never discusses' dealings with the FSA.

But since Lloyds is now mainly possessed by taxpayers, having been rescued in 2008, there are mounting calls for it to be more open with consumers and the public.

Peter Vicary-Smith, Chief Executive of Which?, the dominant consumer lobby group, verified that he will be writing to Lloyds' Chief Executive, Eric Daniels this week, posing directly, if the bank is one of the two quoted by the FSA.

Vicary-Smith will also write to Royal Bank of Scotland, the other bank that needed bail out by the public.