THE number of patients waiting more than the target time of six weeks for key diagnostic tests has ballooned by almost 300 per cent in the last two years.

Official figures show 18,644 patients were forced to wait six weeks or more, compared to the 4,750 who had to wait longer than the Scottish Government's target in June 2016.

Meanwhile, more than a quarter of inpatient or day hospital patients waited more than the 12-week maximum promised by the SNP during the last three months, leading to claims the system is “in tatters”.

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Opposition parties seized on NHS data showing a record low of 74.6 per cent of patients were treated within the guaranteed period laid down in law.

In one health board, NHS Forth Valley, the Treatment Time Guarantee (TTG) was met in barely half of all cases in the three months to June.

Cancer Research UK branded the increasing number of people waiting for tests "deeply concerning", with Labour blaming the NHS "staffing crisis".

Labour said the waiting time guarantee had been broken 35,129 times so far this year, with a record 21,482 waiting more than 12 weeks in the last quarter.

The TTG was created in 2012 by then Health Secretary Nicola Sturgeon to give patients a right to treatment within 12 weeks for conditions such as knee and eye operations.

However it has been routinely broken, without legal consequences for the health boards concerned, leading to complaints that it is a guarantee in name only.

The 12-week treatment time guarantee has been missed repeatedly

New figures from the health service's statistics branch ISD Scotland showed inpatient and day cases seen inside the 12-week period were the worst on record. NHS Forth Valley met the guarantee in only 56.1% of cases.

Scottish LibDem health spokesman Alex Cole-Hamilton MSP said the guarantee system was “in tatters” and demanded an apology from the First Minister.

He said: “Performance has plummeted to the worst on record and the sustained decline shows no sign of abating. People were told there would be redress on the 'rare occasions' things go wrong, but there is no sign of any solution for those who were systematically failed or those still waiting for treatment.

“Literally every week I have people come to see me who have been informed of the guarantee but ended up waiting over a year.

"The First Minister should issue an apology to the tens of thousands of people to whom her Treatment Time Guarantee has meant nothing."

Labour MSP Anas Sarwar added: “In 2012 the SNP made a promise to the people of Scotland that they would have a legal right to treatment within 12 weeks.

“That law has been broken 35,129 times in 2018 already.

“New Health Secretary Jeane Freeman has an overflowing in-tray of issues in the health brief, but these broken laws sum up the problem – our NHS staff don’t get the support they need so thousands of patients miss out on the care they deserve."

Other statistics showed that in June 2018 only five of the 15 NHS boards who submitted valid data met the 18-week Referral To Treatment standard, which sets out how long patients should have to wait after being referred for treatment by their GP.

The Scottish Government highlighted new figures on patient satisfaction which showed 86% rated their experience positively, and more than a third giving it full marks.

People were particularly pleased about experiences with the staff who cared for them, with positive ratings at 91 per cent, the highest level since 2014.

Health Secretary Jeane Freeman said: “Our NHS does a great job. Patients are telling us that our hard working staff are providing high levels of hospital care, which focuses on good communication and a personalised approach.”

On the TTG figures, she said: “Meeting the challenge of improving performance and reducing waits requires the twin approach of investment and reform.

“That’s why we recently allocated an additional £6m to reduce waiting times for endoscopies, with a focus on the most urgent patients, including those with suspected cancer.

“That is seeing immediate steps to cut the number of people across Scotland waiting for diagnostic testing, with health boards working towards reducing the number of patients waiting over six weeks by 5,000 by the end December 2018.

“This investment followed a package of measures – including £50m extra funding – to reduce long waits for treatment. We will continue to work with boards to ensure that this additional funding delivers the improvement needed.”