Bradford's only casualty unit is being swamped by night-time emergencies.

Now concerned medics have launched an urgent inquiry into why the number of patients rushing to accident and emergency has rocketed by 20 per cent in the past four years.

Doctors fear the situation is likely to get worse - with the busiest time of the year set to hit Bradford Royal Infirmary and the opening of a new £4 million A&E unit imminent.

The rush of accident and emergency cases is having a knock-on effect - leading to longer waiting times for less serious cases and violence against doctors and nurses.

A&E consultant Pete Bradley today made an impassioned plea for those thinking of dashing to casualty to hold off and visit their GPs - unless it was a real emergency.

The department looks set to break the 100,000 patient barrier for the first time this year, with 48,887 new casualties already seen at Bradford Royal Infirmary in the first six months of the year.

"We're seeing more people with major injuries and illnesses at night. It's people with things like severe asthma or severe abdominal pain," said Mr Bradley.

"The problem with them attending at night is that they're very labour intensive. They take far more time than if you come in with a broken ankle, and that means an in-built delay for minor things. If you come in with a cut finger you are likely to wait longer."

He added: "It impacts on violence and aggression too. Patients who are violent are often patients with minor injuries who get frustrated at waiting a long time. Sometimes there's the effect of drink too."

Frustrated patients facing long waits fail to understand the stressful battle to treat more urgent cases, Mr Bradley said.

"One car crash could put up the waiting time by an hour and a half because it takes a lot of resources," he said.

The figures have rocketed despite the department being housed in temporary accommodation while the new £4 million unit is built - and despite staff's pleas for patients to avoid clogging up casualty if they can be treated by their GP.

Mr Bradley also said he had heard that Bradford residents living on the district's borders heading to A&E departments in other towns to avoid the poor accommodation.

He fears once the new department is open in late September they were likely to return to BRI. The department will also have a dedicated children's unit. "That increases the number of children who come and I think that will rise exponentially.

"We do have worries that people will use the department inappropriately but we will cope with that. If people come and see us with a long-term complaint, the best place to treat them is at the GP's surgery. The A&E gives a snapshot, the GP knows all their history, what has worked and what hasn't."

The staggering 100,000 figure does not include people who have to go back to A&E clinics for follow-up appointments, which is likely to add at least another 8,000 cases a year to the medics' already heavy workload.

The department is one of the four or five busiest in the country.

Lesley Sterling-Baxter, chief officer at health watchdog Bradford Community Health Council, said: "I'm surprised the figure has gone up."

She said a lot of work was underway in Bradford with more clinics in primary care, clinics near people's homes, in a bid to reduce A&E attendances. "A lot of work is being done on it nationally," she added. And NHS Direct was available in the area to offer health advice and information for people worried about their own or their family's health.