Patients admitted in an emergency to hospital on the weekend are older and more dependent than those admitted during the week a study has found which will add to the row over a seven day a week NHS hospital service.

The study showed the average age of those admitted on the weekend was 68, compared with 65 during the week, and they were more "functionally dependent" than those admitted on a weekday.

The BMJ research, published in the Emergency Medicine Journal, looked at 536 patients from the Royal Victoria Hospital in Belfast.

It concluded that the major differences in the age and functional dependence of patients admitted to hospital at weekends "may fully or partially explain the increased mortality that has been publicised".

However the experts also questioned whether increasing the numbers of staff at the weekend would make any difference to the survival of patients.

In November 2015, a study found babies born in NHS hospitals at weekends are more likely to be stillborn or die in the first week of life than those delivered Monday to Friday.

A different study in the BMJ in September showed that around 11,000 more people die every year within 30 days of admission to hospital on Friday, Saturday, Sunday or Monday compared with other days of the week.

These findings have been used by Health Secretary Jeremy Hunt to spearhead a better weekend service in hospitals, which has in turn led to discord among junior doctors who went on strike.