Unrest among ambulance staff at new shifts introduced by Great Western Ambulance Service (GWAS) contributed to a significant fall in response times to emergency 999 calls.

The shift changes were introduced in November across Wiltshire, Gloucestershire and Avon and figures showed response times to Category A (life-threatening) calls fell from 73.8 per cent in November to 64.7 per cent in December.

The national target is for ambulances to reach a patient within eight minutes 75 per cent of the time.

Performance in Wiltshire was the best among the three sectors, at 69.3 per cent, down from 74.7 per cent. Avon had the biggest drop, from 71.7 per cent to 61.9 per cent while performance in Gloucestershire was 64.5 per cent compared to 77.4 per cent.

GWAS also said the drop in performance was due to bad weather and a flu bug among staff which resulted in high sickness levels.

David Whiting, speaking on his final day as chief executive of GWAS last Friday, said: “There’s no doubt the changes we have made to accident and emergency redesign, particularly the roster changes, had not settled at the end of November and into December.

“There was a lot of unrest and industrial relations issues, particularly in Avon, and we saw productivity, particularly in that patch, decline significantly.”

Mr Whiting said he was confident the changes to shift patterns would result in better performance.

“These changes are starting to bear fruit for patients. Our current performance is exceptionally good.

“The last 14 days has been the strongest we have seen in the trust’s existence, with performance levels of 80 per cent to Category A calls,” he said.

However, Mr Whiting said December’s poor performance may mean GWAS does not meet the national target of 75 per cent for the financial year ending in March.

He said: “It’s possible. We will need to stretch ourselves further to get over the line. Our current level of performance, although very good, might not get us over the line.”