At Southwark Crown Court on December 1, Mindaugus Lenartavicius, was sentenced to jail after pleading guilty to a charge of arson at the branch of RBS in Threadneedle Street at an earlier hearing.
The court heard how Lenartavicius, 21, from Palmers Green North London, was seen pulling out a lighter and repeatedly flicking it alight on to set window blinds on fire.
The court had earlier accepted his not guilty plea to a charge of being reckless as to whether life was endangered.
City of London Police detective chief inspector Steve Chandler says: “Lenartavicius came to the UK, not to demonstrate peacefully, but to cause damage and gain publicity by any means.
“He did not give thought to the danger he placed our community in and quite rightly he pleaded guilty to these selfish actions. This was a thorough investigation that has resulted in justice being done.”