THE UK's population has risen to more than 63 million, according to estimates made after the first results from last year's census were published.

The population of England and Wales leapt by 3.7 million over the last decade to 56.1 million on census day last year, signalling the biggest growth between censuses since the headcount began in 1801.

A further 1.8 million people were living in Northern Ireland, according to the official record taken on March 27 last year.

The first official findings from Scotland's census are not due to be published until December but the latest estimate in June 2010 suggested a population of 5.2 million, meaning the UK's population has surpassed 63 million for the first time.

The Office for National Statistics said the growth south of the Border was fuelled by migration, rising life expectancy and a rise in fertility rates. The figures showed an ageing population, with more over 65s than ever, with one in six now in this age group in England and Wales.

Sir Andrew Green, chairman of Migration Watch UK, said: "We now find even the official numbers previously understated the scale of net migration by 14% and even this does not account for the illegal immigrant population."

But Matt Cavanagh, the Institute for Public Policy Research (IPPR), said: "Although this is the biggest increase in population size, it is broadly similar to the rate of increase between 1910 and 1970, and only half the average rate of increase between 1801 and 1910."