999 calls for ambulances rose by 13.04 per cent last month, compared to the same time in 2015.
The East of England Ambulance Service NHS Trust (EEAST) received 15,392 emergency calls in Hertfordshire in March, up from 13,616 last year.
EEAST serves six counties, and across Beds, Cambs, Essex, Herts, Norfolk and Suffolk the number of call-outs increased by 21 per cent.
Rob Ashford, acting director of service delivery for EEAST, said: “We continue to face unprecedented demand on our service. We have increased the number of clinicians in our control rooms to give medical advice and ensure that we are sending ambulance staff to life-threatening and serious medical emergencies.”