Wexham Park Hospital may be downgraded to provide only an A&E service in the future, a health boss has said.
Ed Donald, chief executive at Royal Berkshire Hospital, said specialist treatment for some life-threatening conditions would be based at Reading.
He said the Slough hospital was cutting jobs and could not continue as it was.
Heatherwood and Wexham Park Hospitals NHS Foundation Trust has so far declined to comment.
Mr Donald said the Royal Berkshire Hospital was "ideally situated" to serve as the county's main "hyper-acute centre".
He added: "I think we're going to see a couple of things in the next few years - I think we're going to see a greater integration of care and we're going to see a greater specialisation of care.
"I think in terms of greater specialisation, we will to see the emergence of something called hyper-acute centres, which are there to save your life and do a bit more than your normal district general hospital acute service.
"Reading is ideally situated for that because we have a population of 800,000 to serve and we are within an hour travel distance for 800,000 people."
He continued: "Heatherwood and Wexham Park are reducing their workforce by some 450 staff this year, not over a three to four year cycle, this year.
"They're starting to think through 'what's the scale of our operation', it's slimming down.
"Yes, they'll need an A&E department for Slough, but that's all they need."