Britain’s population grew by 420,000 last year – a rise equivalent to a city the size of Cardiff. The growth is due to immigration and the biggest baby boom in 40 years, official figures shows. About 63.7million people live in Britain, said the Office for National Statistics. The population grew most in London, with an extra 100,000 residents now in the capital. There were 254,000 more births than deaths last year. In addition, 165,600 more people entered the country than emigrated. Many migrants to Britain are from China, India, Germany, USA, Pakistan, Poland and Australia. Midwives are also feeling the strain from the baby boom. The number of children per woman, known as the fertility rate, rose to 1.94 last year from 1.93 in 2011. The chief executive of the Royal College of Midwives, Cathy Warwick, said another 5,000 midwives were needed in England to cope with the increase. ‘In Scotland, Wales and Northern Ireland, births are at recent highs,’ she said. ‘England births continue to boom, with the proportion of births to older women growing faster than for younger women. ‘This places pressure on maternity services and we are struggling to provide high-quality antenatal and postnatal care. ‘Despite welcome increases in the numbers of midwives recently, there is still a shortage.’ The population of England now stands at 53.5million. A further 5.3million live in Scotland, 3.1million in Wales and 1.8million in Northern Ireland, making Britain the third-most populous EU state. UKIP leader Nigel Farage said the figures proved the government hasn’t got a grip on immigration. ‘The results of this increase in population can be felt in communities up and down the country as public services struggle to cope with increases in demand,’ he said.