By Dominic Casciani
Community affairs reporter, BBC News
Is Britain segregated? Do people live in ghettos defined by their race or religion - and is this something to fear?
Is segregation a state of mind?
Long before last year's bomb attacks in London a debate had been growing over whether or not citizens of multi-racial, multi-faith Britain were living "parallel lives".
Nobody has come up with any clear answers - in fact the London bombings seem to have made the debate even more complicated.
But organisers of a conference about the experience of Muslims in British cities, say it's time we re-thought what is meant by segregation and ghettos.
"Muslims may live in one area, they may go to Halal shops, they may go to the mosque," says Dr Tasleem Shakur, one of the organisers of the conference at the University of Central England in Birmingham.
"They are quite happy and do not need to necessarily step outside of that community and it is not causing any harm."
As such Dr Shakur believes the key issue is not necessarily the spaces in which people physically live - but the spaces people occupy in their heads.
He says many British Muslims live in an "Islamic psyche" which, in the case of British-Pakistanis is physically in the UK but mentally "they effectively like to think they are in Karachi, living in a virtual Islamic world".
"There's a dearth of knowledge about how segregation really works," says Dr Shakur of Edge Hill University in Lancashire.
As an example, he says mosques are viewed suspiciously by some authorities - but in reality, part of their role is to provide "services to the community which government has denied them".
"The more government misunderstands this psyche, then the worse the problem becomes because it prevents the growth in confidence needed to become part of the mainstream."
So are there any ways of projecting forward what happens to such communities?
Trevor Phillips: Segregation warning sparked debate
Dr Laura Vaughan of University College London is an architect by training who uses scientific methods to calculate how cities become more or less segregated. She says that Britain needs to look at its history.
"I came across this book from 1900 called The Jew in London," she says.
"What is fascinating about the maps is that it shows the so-called 'Jewish ghetto' of 100 years ago. But Jewish people just don't live [in numbers] in those areas anymore."
Dr Vaughan has used census records to chart the long, slow process of geographic integration of the Jewish community, as it moved away from its initial, tight-knit, immigrant base.
"One can be clustered, as the Jewish communities were, but it does not necessarily mean that you are segregated from society."
A great deal of the debate has focused on comparisons between the UK and USA - with disputed research last year suggesting that segregation in the UK was getting worse.
Trevor Phillips, head of the Commission for Racial Equality, warned that Britain was "sleepwalking to segregation". However, other experts rejected that analysis, with Professor Ceri Peach of Oxford University labelling it as "alarmist".
So what is the true picture? Some US minorities comprise 90 to 100% of the population in their neighbourhood and may rarely see the face of someone with a different colour to themselves.
In contrast, the recognised method of monitoring segregation in British cities shows the situation has either improved or stayed the same over the past 15 years.
"My general theory is that immigrant communities develop naturally in a location that enables slow integration over time," says Dr Vaughan.
"When we look at the Bangladeshis in London's East End, people say they have been there since the 1970s. Well it takes time and we forget that. It's possible that we will see Muslims following the same trajectory as the Jewish communities."