British shadow business secretary Kenneth Clarke says the merger of HBOS and Lloyds TSB has been a "disaster".
Lloyds said on Friday its HBOS unit made a pretax loss of Stg 8.5 billion pounds last year due to a bigger than expected rise in bad loans, which wiped a third off its value.
The result has raised fears more state help would be needed.
Mr Clarke said on Saturday that the Lloyds Banking Group might be in a more comfortable position now if the government had not forced through what he called a "shotgun marriage."
He said they should never have been allowed to merge.
"Lloyds TSB was a boring bank, it was a steady bank, it hadn't done silly things," he said.
British finance minister Alistair Darling said on Saturday at a meeting of Group of Seven finance ministers in Rome, that banks were best left in the private sector.
He has said the government had to intervene quickly at the time of the merger to stop a collapse of the banking system.
HBOS was bought by Lloyds TSB in September last year. The deal was brokered by the British government.
The group is 43% owned by the British taxpayer.
The Treasury said there were no meetings planned between Mr Darling and senior bankers this weekend.
