The number of pensioners in Ealing is set to rise by 5,000 in the next 10 years.
According to figures released by the Department of work and pensions, there are currently 35,000 pensioners in the borough, and by 2020 this figure will increase to 40,700.
More people will also be reaching their 100th birthday as the state pension celebrates its centenary in 2009.
The Minister for Pensions and the Ageing Society, Rosie Winterton, said: "It is incredible to think that one in four babies born today could live to 100.
"People live longer and want more from later life and these days, people can spend a quarter of a century getting their state pension."
From April, the basic state pension will go up by 5 per cent and people on a full pension will see their weekly income go up from £90.70 to £95.25.
Pension credit will also increase from £124.05 to £130 per week for a single pensioner.
For more information on pension reform, visit www.dwp.gov.uk/pensionreform/