London , England ( CNN ) -- Hit the road , Jack . Last year 's most popular name for baby boys in England has been knocked off -- by Mohammed . That 's not immediately obvious from data put out this week by the Office of National Statistics , which declared Wednesday that Oliver was the single most popular name for boys born in 2009 . But a CNN analysis of the top 4,500 boys names shows that , when different spellings of the name are lumped together , Mohammed is No . 1 . Oliver and variations come second , followed by Jack , Thomas , Charles , Harry , William and Daniel . The United Kingdom is about 4.6 percent Muslim , with just under 2.9 million Muslims according to the Pew Forum on Religion & Public Life . And Muslims have a strong tendency to name their sons Mohammed . `` The first reason why people keep the children 's name Mohammed is because of their love of the prophet Mohammed , because they want to emulate him , '' said Imam Abdullah al-Hasan of the East London Mosque . `` They want to copy him not just through his behavior and conduct , but also his name , '' said the imam , who is thinking about naming his own newborn son after the founder of Islam . The Muslim population has risen rapidly in Western Europe in the past 20 years , according to the Pew Forum on Religion & Public Life . From under 10 million in 1990 , it 's gone up to about 17 million today , the think tank said in a report last month . That has be accompanied by tensions ranging from racial violence in parts of England to legal restrictions like banning the burqa in France and banning minarets in Switzerland . But al-Hasan says Britain has nothing to fear . `` One message I would give to them is that you should n't be surprised . You should n't be scared . You should n't be frightened or anything like that , '' he said . `` It shows that Islam is here to stay in Britain . Islam is here to stay in Europe , '' he said . `` It 's not alien from the Western society . It 's not alien to the British context . '' CNN 's Brittany Harris , Erin McLaughlin and Atika Shubert contributed to this report .
NEW : Muslims name their sons Mohammed to honor the founder of the religion , an imam says . NEW : The Muslim population of Europe is rising quickly . New : A new study finds that a quarter of all European immigrants are from countries with large Muslim populations. The United Kingdom is about 4.6 percent Muslim .