A vigil to say goodbye to the country’s oldest fire station is scheduled to mark its closure on Thursday morning in “one of the saddest days” in the service’s history.

Current and former firefighters are set to join Fire Brigades Union (FBU) members and councillors outside 100-year-old Clerkenwell Station at 8.30am before the final watch are asked to leave an hour later.

The station is one of 10 set to be canned across London – along with the loss of more than 550 firefighters and 14 fire engines – as the Mayor of London Boris Johnson looks to slash £45million off the budget over the next two years.

A firefighter who asked not to be named said: “We’ll be doing the last shift, we finish at 7.30am then they’ll kick us out of the station at 9.30am. I don’t understand how they’re going to do it, there’s too much stuff to do before they close the station.”

Cllr Paul Convery, Islington Council’s executive member for community safety, said it was “completely unprecedented” for fire stations to close in London, which he believed raised doubts about whether adequate cover would be provided from other sites.

He said: “It’s true there are fewer fires in London, but there hasn’t been a significant drop in major incidents, or those requiring multiple appliances.”

Paul Embery, London regional secretary of the FBU, said: “Mayor Boris Johnson will have blood on his hands. It will be only a matter of time before someone dies because a fire engine did not get to them in time.

“You cannot close 10 fire stations and slash nearly 600 firefighter jobs without compromising public safety. These stations have protected generations of Londoners, and they are as necessary now as they ever were. It will be one of the saddest days in the history of the London Fire Brigade when these stations close their doors.”

James Cleverly, chairman of the capital’s fire authority, said: “Londoners will continue to receive one of the fastest emergency response times in the world from the London Fire Brigade. If you dial 999 and need a fire engine, we still aim to have one with you within six minutes and a second, if needed, within eight.

“The brigade is faced with significant budget cuts which mean that changes to the service are inevitable and we are able to make those changes without compulsory redundancies. The firefighters based at the stations closing will now transfer to other stations and continue the excellent work they do to prevent fires, which is vital in changing the behaviours that start fires in the first place.”

A legal challenge to the closures, led by Islington along with six other boroughs last year, failed so the cuts will go ahead.