Government cuts to social services could be the “largest factor” in the biggest annual rise in deaths in England and Wales for nearly half a century, according to an adviser to Public Health England.

The new preliminary figures, from the Office for National Statistics, claim that mortality rates last year rose by 5.4 per cent compared with 2014 – equivalent to almost 27,000 extra deaths. The increase is the highest since 1968 and took the total number of deaths in 2015 to 528,340.

Death rates in England and Wales have been steadily falling since the 1970s but this trend has been reversed since 2011.

Advisers to Public Health England told the Health Service Journal (HSJ) that an investigation should be launched following the new statistics. They added that the figures show the elderly, especially women, were now bearing the brunt of a growing crisis in the National Health Service and cuts to social care.

Professor Danny Dorling, from Oxford University and an adviser to Public Health England on older age life expectancy, said: “When we look at 2015, we are not just looking at one bad year. We have seen excessive mortality - especially among women - since 2012.”

He added: “I suspect the largest factor here is cuts to social services - to meals on wheels, to visits to the elderly.

"We have seen these changes during a period when the health service is in crisis, while social care services have been cut back.

"The statistics clearly show that this is the biggest rise we have seen since the 1960s. But this may well turn out to be the greatest rise since the Second World War, taking into account the sustained nature of the rise, as well as other factors, such as the trend for immigration of older people in the 1960s."

It was revealed last year that a £1.1bn cut to adult social care was leaving the country’s most vulnerable people “in jeopardy”. The warning came amid reports that councils had slashed their adult social care budgets by 21 per cent over the last five years.

Dominic Harrison, an honorary professor at Central Lancashire University and Blackburn said to the HSJ that the changes were a “strong and flashing amber warning light [that] something is making the population more vulnerable to avoidable death”.

Mr Harrison added: ‘One of the things this data may be telling us is it is just not possible… to contain costs, improve quality, reduce inequality and improve outcomes within such a rapidly diminishing resource envelope… we need to understand exactly what is happening if we are to prevent it continuing.’

Caroline Abrahams, charity director at Age UK said a full investigation was needed urgently. She added: "These figures suggests something is going badly wrong…we owe it to older people to investigate why last year's statistics are so unusually high and to take firm action to address the causes, whatever they may be."