A senior Tory has called for a "grown-up" debate on immigration after a race equality campaigner said the pursuit of 'multiculturalism' should be ditched.
Some imams do not speak good enough English, says Labour's Lord Ahmed
Alan Duncan said diversity should be welcomed but argued past assumptions about the UK's need for immigration should now be debated.
The Commission for Racial Equality's chairman has also said it is time to stress common strands of Britishness.
Lord Falconer meanwhile highlighted the financial benefits of immigration.
He added: "People who come here should plainly be completely free to keep their cultural identity as long as it does not rub up against any of the laws of this
Mr Duncan said one question which needed to be asked was what motivated a few British Muslims to last week burn the union jack in Regents Park, Central London.
"What is it that makes third generation Muslims in one of our cities hate this country and prefer Osama Bin Laden?
"This is a serious social problem that deserves serious political attention."
Labour peer Lord Ahmed meanwhile called for government funding to train imams - Muslim spiritual leaders.
He told Today that imams needed to have a decent command of English and understand British culture if they were to connect with young Muslims.
"Why is it in every other job we have to sit tests? Why is it for every other job we have to have minimum qualifications and for imams we can't do that?"
Mr Duncan, who is Conservative constitutional affairs spokesman, said in the past people had made a series of assumptions about the benefits of immigration.
"I think the whole question now can legitimately turn, without I hope political rancour, to some of those questions that need to be asked," he said.
"It is asserted that we need immigration. It is asserted that all immigrants make a contribution. It is also asserted that we must give refuge to all who are
"These bold and unquestioning assertions I think now,
particularly in the context of global terrorism in which all of this is now being argued, really have to be studied and discussed in a grown-up,
British people should be able to celebrate their culture without it seeming offensive to others, he added.
Trevor Phillips - who chairs the Commission for Racial Equality - meanwhile repeated his assertion that the term "multiculturalism" suggested separateness and had ceased to be useful in modern Britain.
It was necessary to "assert a core of Britishness" for all citizens which meant stressing shared values such as believing in democracy and the rule of law.
One of the founding principles of the commission Mr Phillips oversees is multiculturalism - a policy followed by successive government since the 1960s.
It was originally designed to strengthen engagement and relations between Britain's different ethnic communities.
But Mr Phillips said the term suggested "separateness" and was no longer useful in present-day Britain.
"We are now in a different world from the 60s and 70s," he said.
"For instance, I hate the way this country has lost Shakespeare. That sort of thing is bad for immigrants.
"They want to come here not just because of jobs but because they like this country - its tolerance, its eccentricity, its Parliamentary democracy, its energy in the big cities.
"They don't want that to change," he said.