Dozens of patients had to wait more than eight hours at Tayside and Fife emergency departments in one of the toughest weeks for the NHS on record.
Scotland’s A&E sites posted their worst waiting time performance data since weekly reporting began nearly three years ago.
Health chiefs have been forced to cancel operations and deploy office workers onto the frontline as hospitals face “unprecedented demand” this winter.
In Tayside, numbers turning up to A&E increased by 11% in the week to December 31, compared with the same week the previous year.
Thirty patients in Fife endured an eight-hour wait to be seen in that week, with four of those having to hold out for 12 hours, according official government figures.
Thirteen patients were waiting eight hours or more in Tayside.
The proportion of those seen within the flagship four-hour waiting target fell from 97.0% to 87.3% in the last week of 2016 and 2017 respectively in Tayside.
In Fife, performance fell from 90.8% to 81.5%. Both boards fared better than Scotland as a whole, where only 78% of patients were seen and either admitted, transferred or discharged within four hours.
In a statement to Holyrood on Tuesday, Health Secretary Shona Robison was forced to defend her government against accusations it has deprived the health service of the resources it needs.
Scottish Conservative shadow health secretary Miles Briggs said the figures “are nothing short of a disgrace”.
Anas Sarwar, for Scottish Labour, said: “NHS staff are not getting the support they need from the SNP government in Edinburgh and as a result over 100,000 patients had to wait more than the A&E standard in 2017.”
Ms Robison said Scotland’s A&E departments have the best-performing in the UK over two-and-a-half years but “exceptional demand” has seen targets missed.
“My local A&E department in Ninewells has never fallen below 95% (of patients seen within four hours).
“Over the last two weeks it has, because of the pressures of fractures, of flu and unprecedented winter pressures.
“I think most reasonable people would understand that.”
Tayside and Fife are among the health boards which have cancelled non-urgent operations over the festive period to free capacity.
Lesley McLay, Tayside’s chief executive, said: “Despite these increases in patient activity, I am very pleased to say that our teams in hospitals and in communities have pulled together to deliver the highest standard of care for patients and their families.”
Earlier, Ms Robison told MSPs she wants to be able to retain the ability to compare the performance of the NHS in Scotland with other parts of the UK.
She has been criticised by political opponents for pointing to NHS England’s woes when questioned about the performance of Scotland’s health service.
