Travers Smith and One Essex Court's Lord Grabiner QC have released the findings of their report into the Bank of England's conduct in the foreign exchange market, exonerating bank officials from claims they were involved in or were aware of rate rigging that was taking place.

Travers oversaw the extraction of more than 1.8 million documents and 87,000 telephone calls from the Bank's IT systems, but the report concluded that no Bank of England official had engaged in any unlawful or improper behaviour in the FX market between 2005 and 2013.

Grabiner interviewed 10 current or ex-Bank officials and 18 current or ex-employees of banks who attended meetings over the period that were relevant to the Financial Conduct Authority's inquiry into forex market manipulation.

Grabiner did criticise one Bank official, however, former chief currency dealer Martin Mallet, who was aware that bank traders "were sharing aggregated information about their client orders for the purposes of a practice known as "matching"" – leading to a heightened risk of improper conduct – but did not escalate the matter appropriately.

Mallett was fired by the Bank this week. He "did not act in bad faith" though, according to Grabiner, and "was not involved in any unlawful or improper behaviour, nor was he aware of specific instances of such behaviour."

Grabiner's primary recommendation was that the Chief Dealers' Sub-Group, part of the Bank's foreign exchange joint standing committee, should improve minute taking at its meeting in order to flag up issues to senior staff earlier.

Travers Smith declined to comment on the report, which came on the same day that six banks, HSBC, Royal Bank of Scotland, UBS, JP Morgan Chase, Bank of America and Citibank, were fined a collective £2.65bn by regulators for their traders' attempts to manipulate forex rates.