A museum at Bletchley Park, site of the World War Two code-breaking success, is to cut up to a third of its jobs after losing almost all of its income during lockdown.
Up to 35 jobs at all levels and in each department are said to be at risk.
Chief executive officer Iain Standen said the Bletchley Park Trust had “exhausted all other avenues”.
Workers at the Buckinghamshire site were responsible for decoding enemy codes during the war.
The site became a museum in 1994.
The trust, which has 118 employees, expects to lose £2m in income this year.
When the coronavirus lockdown began, it furloughed 85% of its staff and managed to secure some additional funding from the National Lottery Heritage Fund.
It closed on 19 March and reopened on 4 July, although with reduced visitor numbers due to social distancing.
Savings have been made by reducing marketing, new exhibitions, travel, IT and printing costs, but this only helps in the short term, according to the trust.
Mr Standen said: “The economic impact of the current crisis is having a profound effect on the trust’s ability to survive.
“We have exhausted all other avenues, and we need to act now to ensure he trust survives and is sustainable in the future.”
A staff consultation on the job losses will begin next week.
Find BBC News: East of England on Facebook, Instagram and Twitter. If you have a story suggestion email eastofenglandnews@bbc.co.uk