The number of over-65s in a job has reached a record one million, figures have revealed.
Unions said with almost a million young people out of work it was clear there weren't enough jobs, while experts believed people were working longer to top up inadequate pensions.
The Prime Minister said the Government had a "good record" on jobs, as unemployment fell by 5,000 to 2.5 million and the numbers claiming jobseeker's allowance shrank by 8,600 last month to 1.5 million. A record 29.7 million people are in work after a rise of 24,000 in recent months.
The Office for National Statistics (ONS) figures showed over 65-year-olds still in work has topped one million for the first time since records began in 1971.
Almost one in 10 in the age group are working – 615,000 men and 388,000 women.
Jim Hillage, Institute for Employment Studies director of research, said: "While this reflects a welcome willingness among employers to recruit and retain experienced people, it may also reflect the need that some older people have to top up inadequate pension arrangements."
Other data disclosed that public sector employment has fallen by 22,000 to just under 5.7 million. the lowest figure since 2001.
Ministers pointed to a growth in jobs in the private sector, up by 46,000 to 24 million in recent months.
The UK's employment rate is now 71.5 per cent, while 7.8 per cent of the population is jobless, with 22 per cent classed as economically inactive, including students, those on long term sick leave or who have given up looking for work. The so-called claimant count has fallen for seven months in a row and has dipped to its lowest total since May 2011.
The fall in unemployment in the quarter to April was entirely due to men finding work, while the number of women out of a job rose by 7,000 to 1.09 million.
Long-term unemployment has also increased, with those looking for work for longer than a year up by 11,000 to almost 900,000.
Youth unemployment – counting those aged between 16 and 24 – has fallen by 43,000 to 950,000.
