The decision was taken to increase the programme from its previous level of £325bn after a vote earlier this month.
Minutes from the latest meeting show that seven members of the committee voted in favour of the move, with two against.
Governor Mervyn King, Charles Bean, Paul Tucker, Paul Fisher, David Miles, Adam Posen and Martin Weale) voted for increased quantitative easing.
Spencer Dale and Ben Broadbent were the two members who voted against the proposition.
The MPC was unanimous that the bank rate should be maintained at 0.5%.
The minutes said: “On balance, and in light of the potential stimulus provided by the other recent and prospective policy initiatives, these members judged that an additional £50bn of asset purchases was appropriate at this meeting in order to balance the risks to inflation around the 2% target in the medium term.”
The Minutes also saw the committee soften its tone on the prospect of cutting the base rate to below 0.5%.
The committee had previously decided a rate cut was less attractive than an extension of the asset purchase programme.
“The impact of the FLS and other policy initiatives might, in time, alter the committee’s assessment of the effectiveness of such a rate reduction,” the minutes said.
