A spokesman for the South East Coast Ambulance Service (SECAmb) spokesman also thanked staff for their 'efforts and professionalism' over the Christmas period.
They said: “We are experiencing some very busy days and are working hard to respond to patients as quickly as possible. We are prioritising our response to our most seriously ill and injured patients but we are taking longer to reach some patients.
“We urge people to only call 999 in the event of a serious or life-threatening emergency and to use 111 for non-emergencies.
"We have also seen a high number of calls to our 111 service which is working hard to help patients. We would remind people to also make use of 111 online at 111.nhs.uk.
“If you have had to call 999 and are waiting for an ambulance, please only call us back if a patient’s condition worsens.
“We are very proud of our staff and thank them for their ongoing efforts and professionalism.”