Workers at the Bank of England (BOE) walked out on strike on Tuesday for the first time in five decades, over a pay dispute.
Employees working in the central bank's maintenance and security departments, will continue the industrial action over the next three days.
Staff employed in the bank's "parlors" - ground floor offices where BOE Governor Mark Carney and his senior colleagues work - are also involved in the strike.
A last-minute attempt to halt the action at the government's conciliation service Acas yesterday failed to break through. The U.K.'s Unite union has been in dispute with the BOE over a below-inflation 1 percent increase in pay for maintenance, parlors and security personnel.
"Mark Carney should come to the picket lines outside this iconic British bank today and explain why hardworking men and women deserve to face years of pay cuts," Peter Kavanagh, a Unite official, said in a statement on Tuesday.
"They are struggling to pay their bills and feed their families because the bank has unjustly imposed a below inflation or zero pay rise."
Staff wore Mark Carney masks outside the institution's headquarters in Threadneedle Street, London.