The Save Trafford General campaign said the closure of its A&E department is "tearing the heart out of the hospital".
Matthew Finnegan, the campaign's chairman, said the future of the hospital - widely considered to be the birthplace of the NHS - is now "in real danger".
Mr Finnegan said: "These decisions can't just be made by clinicians - they have got to listen to what local people say. And people want an A&E, it's not an unreasonable request.
"Local people will be appalled and disgusted that they have not been listened to."
More top news
The prince laid a floral wreath at one of a group of metal crosses near Wellington Arch in central London.
The group, which also owns Premier Inn, said on Wednesday that it will pursue a ‘demerger of Costa’.
The showers will become more frequent as the day goes on, giving some heavy downpours in places during the afternoon.