When counterfeiting began
The Bank of England started its counterfeiting program in March 2009 with the backing of the then chancellor of the exchequer Alister Darling. A limited company, called the Bank of England Asset Purchase Facility Fund Limited, was set up to try to hide the fact that it was counterfeiting money. The Monetary Policy Committee (MPC) were given the freedom of deciding on the timing and scale of counterfeiting.
The chart below shows the total gilts and corporate bond purchased over time, which totals £895 billion as of December 2021. Left and right-hand axes are on same scale but offset for comparison.
Bank of England Counterfeiting Operations, 11th March 2009 to the 31st of December 2021. Data from the Bank of England
The MPC started with £200 billion of counterfeit money, buying up to £185 billion by December of 2009. This increased to £375 billion by 2014, was further increased to £445 billion following the vote for the UK to leave the European Union in June 2016, and then doubled to £895 billion when the Covid-19 pandemic hit.