Some 40% of non-retired people surveyed – the equivalent of 14.7 million people – said they did not know when they would be able to stop working, up from 38% in 2012 and 36% in 2011.

Worryingly, despite nearing the traditional retirement age, 34% of 55-64 year olds – around 1.8 million people – said they did not know when they will be able to retire.

Overall, the research found that the average age when people say they plan to retire has also increased – to 64 years old in 2013 from 62 in 2009. For people aged over 65 who have yet to retire, their expected retirement age is 71.

Marino Valensise, chief investment officer at Barings, said: “It is clear that uncertainty is increasing for many people around retirement plans, with more people unable to say exactly when they plan to retire and the average age continuing to rise. Significant numbers of people nearing traditional retirement age reported they did not know when they will be able to retire and the worry is that a lack of sufficient financial planning and pension provision combined with increased longevity is having a real impact on a large proportion of the population.”

The research also found that 34% of people – the equivalent of 12.5 million – have no pension, a figure that has remained roughly flat since the annual survey was first carried out in 2008 (35%).

While the number of men with no pension has steadily declined, from 30% in 2008 to 26% in 2013, the number of women has risen, to 42% from 39%. The difference between men and women in the 2013 survey – 16 percentage points – is the second highest on record, topped only by the 19 point difference in 2010.