Edinburgh Royal Infirmary's accident and emergency unit is said to make patients wait longer than anywhere else in Scotland to be seen by a doctor.
This news has only added salt to the wound of hospital chiefs who face mounting criticism over cleaning procedures at the ERI following its branding as one of the dirtiest hospitals in the country earlier this week.
Recent figures have shown that more than a third of patients attending A&E spend over four hours waiting to be seen at the hospital.
However health bosses have shifted blame to the Marmion Pub shootings in Gracemount for influencing the recent figures as it happened while the waiting time survey was taking place. According to then the massive resources needed to cope with the aftermath of the shooting at Scotland's busiest A&E had affected waiting times for other patients.
The Scottish Executive has demanded improvement in waiting times by the end of next year to no longer than four hours between arriving at the A&E unit and admission to hospital, discharge or transfer. The new NHS statistics show that during the seven-day April survey, just under 2000 patients were seen by the doctors at ERI. Among these 1012 minor cases and 946 were serious medical problems.
80 per cent of the minor health complaints were treated within the target time although over half of the patients with a major problem were made to wait much longer. The most frequent reason given for the delay was the lack of availability of beds.
NHS Lothian's clinical director for medicine, Dr Casey Stewart, said: "We are very disappointed not to have met the four-hour standard for this period of what is a very busy time for us. We have worked tremendously hard on innovative ways of reducing the time it takes for us to see and treat patients and we feel the unexpectedly high levels of activity during the days of the census has masked the real improvements we are making in our service.
"The weekend of the census also saw a multiple shooting in Edinburgh that placed unprecedented pressure on the A&E."
Figures released by NHS Lothian did show that during July, 85 per cent of patients attending the A&E were seen on time. A&E at the ERI is already the busiest in Scotland, which sees more than 44 per cent more people than the second busiest department at the Victoria Infirmary in Glasgow.
The survey showed only 65 per cent of patients were seen within the target time at ERI , followed by the Royal Alexandra and Western Infirmary hospitals in Glasgow region, where 72 per cent of patients were seen within four hours.
This was followed by the Western General Hospital, at third position in waiting times where 23 per cent of the 666 patients attending A&E and minor injury clinics waited longer than four hours. Only four per cent of the 709 patients who were seen at the city's Sick Kids Hospital and 11 per cent of the 883 patients attending St John's Hospital in Livingston were made to wait longer than four hours.
Overall, 88 per cent of the 29,412 patients in Scotland were seen within the four hour target. In the Lothians, bed blocking is still a problem with the latest NHS figures showing that 70 patients were forced to remain in hospital longer than six weeks while a care home place was found for them.