"Such manipulation is highly reprehensible, clearly unlawful and may amount to criminal conduct on the part of the individuals involved," Bank of England Governor Mark Carney said in July 15 letter to Lloyds Chairman Norman Blackwell.

Blackwell replied in a July 16 letter, saying the bank shared the Governor's concerns.

"This was truly shocking conduct, undertaken when the bank was on a lifeline of public support," he said.

(Reporting by Matt Scuffham, editing by Huw Jones)