Ammann, 39, was convicted yesterday (13 December) at Southwark Crown Court, and sentenced to two years and eight months in prison after pleading guilty to two counts of encouraging insider dealing and two counts of insider dealing.

The former investment banker was working at the London office of Japanese bank Mizuho in 2009 and had access to sensitive information relating to Canon’s impending takeover of Océ.

Ammann pleaded guilty to coaxing his two girlfriends, Christina Weckworth and Jessica Mang, into investing in shares of the Dutch manufacturer, ahead of the acquisition. The three made a combined amount of nearly £2m.

The Financial Services Authority (FSA) brought charges against all three in July 2011 however both women denied insider dealing and were acquitted last month.

Passing sentence in Amman’s case yesterday, Judge Leonard QC said that his actions "had significant impact on public confidence in the integrity of the market at a time that the City is held in increasingly low esteem".

He added: "Your activities not only cast a cloud over the particular business that employed you but potentially affects the perception of mergers and acquisitions business within the City as a whole."

Canon completed its takeover over Océ in March 2010, assuming a 71% share in the Dutch manufacturer.