Banking giant HSBC is restarting plans to cut around 35,000 jobs worldwide after putting the redundancy programme on hold during the coronavirus crisis.
He said the bank will also freeze the “vast majority” of external recruitment and look to redeploy affected staff where possible.
Mr Quinn told staff: “We could not pause the job losses indefinitely – it was always a question of ‘not if, but when’.”
HSBC announced in February that it was expecting to cut its 235,000-strong workforce to around 200,000 over the next three years as part of a wider restructuring to save £3.6 billion in costs.
It did not give a breakdown of where the jobs would go, but at the time it said there would be “meaningful” cuts in the UK, where the bank employs around 40,000 people.
The group paused the plans in April as the Covid-19 pandemic swept the world.
Mr Quinn said in the memo: “I wish I could say that the next few months will see a return to normality, but that is unlikely to be the case.
“You will have seen that our profits fell in the first quarter and virtually all economic forecasts point to challenging times ahead.
“The reality is that the measures and the change we announced in February are even more necessary today.”
Dominic Hook, a national officer at the Unite union, questioned why HSBC was making the decision now.
He said: “At present, vast numbers of HSBC staff are making massive sacrifices working from home or taking risks travelling into offices and bank branches to help customers.
“Since the start of the Covid-19 crisis colleagues across HSBC have worked tirelessly as key workers to ensure that consumers continue to access financial services to meet their banking needs.
“Now is the time for HSBC to stand by its workforce and recognise these mighty efforts, and see that the bank’s strength lies within its workforce.”
Back in February it was revealed that jobs were at risk at HSBC branches across the UK amid plans to close 27 sites this year.
HSBC said nine in 10 contacts with customers now happen over the phone, via the internet or on its smartphone app, with the number of customers who use a branch falling by a third in the last five years.