More than 1,500 appointments were postponed due to strike action days before Christmas.

University Hospitals Sussex NHS Foundation Trust, which operates the Royal Sussex County Hospital in Brighton, saw more than 400 staff walk out between December 20 and 23 in industrial action by junior doctors.

This forced 1,787 elective procedures to be rescheduled, 194 of which were inpatient appointments.

The day with the most appointments disrupted was December 20, the first day of strike action, with 751 procedures postponed.

The strike also caused Sussex Partnership NHS Foundation Trust to reschedule 30 mental health, learning disability and autism appointments.

Further strikes by junior doctors have been announced by the British Medical Association and are due to take place from 7am on Wednesday to 7am on January 9.

Andrea Lewis, regional chief nurse for NHS South East, said: “This latest round of strike action has put additional pressure on already overloaded health services.

“The three days of strike action, which ended just days before Christmas, has resulted in more than 10,000 appointments and procedures being rescheduled for patients needing care in the South East.

“In addition to having an impact on planned care, industrial action is putting pressure on wider services and prioritising emergency care takes staff away from other areas, such as recovering services.

“The six-day walkout planned in the new year, during what is one the busiest times for the health service, will ultimately bring significant challenges to the NHS as it struggles to provide for patients amid severe disruption.

“As ever, we encourage people to attend A&E and call 999 in life-threatening emergencies, but to use 111 online for other health needs.”

A spokeswoman for Sussex Partnership NHS Foundation Trust said: “We prioritised maintaining our urgent care and inpatient services during the period of industrial action in December.

“A small number of routine appointments with our community and specialist teams were rescheduled for the new year.”

University Hospitals Sussex NHS Foundation Trust was approached for comment.