The Office for National Statistics said over that time, the numbers were relatively stable until 2000 but rose quickly thereafter to a peak of 1.45m in 2010.
The proportion of the older population who are in employment also rose, albeit not as fast as the number of older workers: this proportion went from 7.6% in 1993 to 12.0% in 2011.
A high proportion of these older workers were self-employed: in the last quarter of 2011, 32% of workers aged above state pension age were self-employed, compared with just 13% of those below that age.
Also, workers over state pension age were twice as likely to be working part-time (66%) than full-time (34%).
For those under state pension age, 75% worked full-time and the remaining 25% worked part-time.
This shows that those remaining in the labour market over state pension age work fewer hours, possibly helped by the financial support of their state pension and other pension arrangements allowing them to fit their work around other engagements.
Of the 1.4m older workers above state pension age in the UK in the final quarter of 2011, 39% were men and 61% were women.
However, around two-thirds of these men worked in jobs classed as higher skilled, but almost two-thirds of these women worked in lower skilled jobs.
The higher skilled roles that men carried out included those such as property managers, marketing and sales directors, production managers and chief executives of organisations.
Of all the jobs carried out by men, the two most common were farmers and taxi drivers.
Looking at women, the most common job was cleaners, followed by administration assistants, care workers and retail assistants.
Looking at the period October 2010-September 2011, the South East, South West and East of England had the highest employment rates for workers below state pension age.
The pattern was similar for older workers but with one exception – London.
For the younger population, London only ranked eighth in terms of the employment rate but for older people it had the joint highest percentage in employment of any part of the country, behind the South East, at 14.1%.
The ONS said this may reflect the higher cost of living in London, which might provide an incentive for older workers to work on rather than retire.
Additionally, there tends to be a migratory drift out of London for the older population post retirement such that a higher proportion of those remaining are more likely to be economically active.
At a sub-regional level, the highest employment rate for those above state pension age was in Berkshire, Buckinghamshire and Oxfordshire, at 17.2%, and the lowest rate was in Tees Valley and Durham, at 7.7%.
