Mohammed leaves Michael trailing in the name game

The official count of the baby's names chosen most often last year shows that two different versions were in the top 50 picked by parents.

Mohammed, the most common variant of the Muslim Prophet's name, was the 22nd most popular name for boys.

And the alternative spelling Muhammad entered the list of the top 50 names for the first time, becoming the 44th in the chart.

The rise of Mohammed as a name is an indicator of growing numbers of Muslims in British society in recent years.

There were 3,732 boys named Mohammed or with one of seven other variants of the name in 2000. Last year there were 4,532, and this year 5,936, a rise of nearly two thirds on the Millennium year.

Numbers have been growing as a result of continued immigration from Pakistan and Bangladesh as well as waves of new arrivals from Islamic countries or countries with high Muslim populations in the Middle East and Africa, including Iraq, Afghanistan, Somalia and Nigeria.

Recent immigrants have swelled the Muslim population of around 1.6 million counted by the last national census in 2001.

An analysis published by analysts at the Government's Office for National Statistics earlier this year showed that new migrant familes tend to have children a few years after arriving in Britain, after taking time to find work and settle down.

The increasing popularity of the name may also reflect deepening loyalty to their faith among Muslims.

The ONS breakdown of this year's popular names showed yesterday that Muhammed is the fastest climber in the top 50 chart.

The most common boys name was the same that has topped the list for the past 12 years: Jack. There was, however, a new favourite for girls, Olivia, up from fourth in the rankings last year.

Grace was also an increasingly popular name, up from seven to two in the table, and Ruby shot up to number four from number 15.

Less common were Emily, number one in 2003 and 2004, which slipped from two to five, and Jessica, favourite last year, which fell back to number three.

Thomas, Joshua and Oliver were consistently favoured boy's names, but Harry climbed four places to number five, possibly as a result of the improving public image of army officer Prince Harry.

By contrast Charles dropped out of the boys' top 50, along with Louis, Brandon, Toby and Kieran.

Celebrity fashions are, the lists show, a major reason for parents' naming decisions.

Singer Lily Allen may have helped push Lily up seven places to nine among the girls, with other floral names like Daisy and Poppy also increasingly popular.

Teenage Arsenal footballer Theo Walcott, the surprise pick for England's football World Cup squad, may not have made much impact on the pitch. But his name has entered the top 100 for the first time, chosen by 646 sets of new parents.

Shayne was picked by eight times as many parents this year as last following the 2005 X-Factor TV talent show victory of Shayne Ward.

Keira is now at 33 in the girls' name list and still rising after appearing at number 51 in 2003. This year 1,470 parents picked the name of Pirates of the Caribbean star Keira Knightley.

Some parents also chose to name their girls after the season: there were 864 Summers and 55 Autumns born last year.