Hospitals in Staffordshire, Gloucestershire, Cambridgeshire, London and Surrey are among those affected.
A paramedic in the West Midlands said A&E doors were locked at Royal Stoke University Hospital. The hospital has yet to comment on the claim.
Planned surgery has also been also affected at some hospitals.
Hospitals across the country declared major incidents throughout Tuesday with extra staff being called in to work and, in some cases, surgery cancelled.
Scarborough Hospital, which had declared a major incident on Monday, de-escalated its status on Tuesday afternoon.