Bank of England workers are to stage a four-day strike in a dispute over pay.
Members of Unite will walk out from July 31, the first strike at the bank in over 50 years.
The announcement follows a 95% vote in favour of industrial action.
Unite members working in the maintenance, parlours and security departments will be taking strike action on July 31, August 1, 2 and 3.
The union warned that if the bank fails to resolve the pay row it will be consulting its members across other departments as part of a plan to escalate the dispute.
Unite said staff were angry they have been given a below inflation pay offer for the second year running, while up to a third will get no pay rise in 2017.
"Staff at the Bank of England have made their anger clear by voting for strike action due to their employer's outright refusal to negotiate a fair pay deal for its workforce," Unite regional officer Mercedes Sanchez said.
"The Bank of England now faces its first strike action in over 50 years when staff in vital services across the country will be taking action because of the bank's total refusal to accept that their workforce are struggling to meet their costs of living," the official said.
"The result of the bank's unwillingness to negotiate fair pay will be that the bank's sites, including the iconic Threadneedle Street in the city of London will effectively be inoperable without the maintenance, parlours and security staff."
