Heart attack, stroke and burns victims are among the seriously ill and injured patients waiting over an hour for an ambulance to arrive in England and Wales, a BBC investigation shows.
The delays for these 999 calls – meant to be reached in 18 minutes on average – put lives at risk, experts say.
NHS bosses blamed rising demand and delays handing over patients at A&E.
The research found that the record for the East Midlands Ambulance Service is one of the worst in the country – here one in every eight emergency calls takes the ambulance service more than an hour to respond.