Hospital patients face delays to get treatment as accident and emergency departments struggle to cope with the demand.
Figures from NHS England showed A&E departments ran by Mid Yorkshire Hospitals Trust missed its target on four out of the last five weeks to see 95 per cent of patients within four hours.
Statistics from the week ending Sunday, May 3 showed 4,385 people visited A&E departments ran by the trust, which includes Pinderfields and Pontefract Hospitals.
But just 89.4 per cent of patients were seen within four hours.
The week ending Sunday, April 12 was particularly tough as 83.9 per cent of patients were seen within the target.
That week 740 patients waited between four and 12 hours to be seen in A&E.
The trust reached the target on the week ending Sunday, April 26 when 95.9 per cent of patients were seen within four hours.
Nationally, the 95 per cent target has not been met since the week ending Sunday, September 28.
A&E departments were hit with increased attendances as GP surgeries closed for Christmas.
Kevin Oxley, director of operations at the Mid Yorkshire Hospitals NHS Trust, said: “Like many trusts across the country we are finding it a challenge to meet the national 95 per cent target at this time.
“Mid Yorkshire has the fourth busiest A&E departments in the country and while we know that sometimes patients are having to wait longer that we would like.
“We are doing everything possible to make sure that they are treated promptly and safely. We are facing increased demand for our services and we’re asking people to think carefully about whether A&E is really the best place for their condition.
“A&E departments are for life-threatening and emergency conditions such as heart attacks, strokes, breathing problems and serious accidents. We need to make sure that A&E services are free to help the people who really need them.”