The statistics point to the ageing nature of the UK's society
People aged over 60 in the UK outnumber children for the first time, according to official figures.
The Office for National Statistics revealed that 13,262,256 people were 60 or over in mid-2007 - up from 12,928,071 the previous year.
Meanwhile, the number of under-18s fell from 13,119,654 to 13,111,023 over the same time period.
Help the Aged said an older population would require social care reform and the end of "arbitrary" retirement ages.
Those currently defined as pensioners - men aged above 65 and women aged above 60 - make up 19% of the population, compared with 18.9% for children below the age of 16.
Chichester has the highest concentration of pensioners in England and Wales, with more than 32%.
The growing number of older people is partly due to a fall in the annual number of deaths - from 599,000 in 2001 to 571,000 last year.
The over-80s in particular are living longer.
They were the fastest growing age group, the ONS said, accounting for more than 5% of the population.
The number of over-80s has risen by more than 1.2 million since 2001, largely due to medical advances that have improved survival rates.
Mervyn Kohler, special adviser at Help the Aged, said: "The key task for policy makers going forward is to ensure that older people can increasingly play an active role in our ageing society.
"The days of assuming older people are dependants must now come to an end."
He added that "an ageing society is a fact of life which should be welcomed and embraced, not treated with concern".
But Age Concern has pointed out that as people are living longer many will experience longer periods of ill health in later life.
The government has suggested that a compulsory social insurance scheme could be one way to pay for the costs of caring for older people.
Fewer East Europeans
The ONS also released figures on migration to and from the UK, showing that, overall, immigration has increased.
Net immigration was 199,000 in 2006-7, compared with 187,000 in 2000-1.
EAST EUROPEAN MIGRANTS
Second quarter 2008: 40,000
Second quarter 2007: 54,000
Second quarter 2006: 56,000
Source: Office for National Statistics - number of worker applications
A record number of long-term migrants - some 605,000 - arrived in Britain, up from 591,000 in the previous 12 months.
Emigration also hit a new high, with some 406,000 people leaving in the same period
The Home Office released separate statistics on Thursday which showed that the number of people coming from Eastern Europe to work in Britain has reached its lowest level since EU expansion in 2004.
Between April and June 2008 there were 40,000 applications - a drop of 14,000 from the same period in 2007.
Britain's population as a whole rose by nearly two million between 2001 and 2007, the ONS said.
There were 60,975,000 people in Britain by the middle of last year, up 388,000 on mid-2006.
Rates of population growth varied widely across the UK.
Some parts of England - including Westminster and south Derbyshire - saw population growth as high as 12%, while in other areas, like Sunderland and Burnley, resident numbers fell by 2%.