A senior cabinet minister has questioned whether the Labour Party's "tolerance" has led to community breakdowns.

Speaking at the party's annual conference in Manchester on Tuesday, leader of the Lords Baroness Amos said that while Britain's diversity was to be welcomed, "we didn't recognise the limits of multiculturalism early enough".

The peer and first black female member of the cabinet claimed that the July 7 suicide bombings in London last year had forced the left to "ask ourselves new questions".

"And we haven't felt comfortable doing it," she argued.

"Has our tolerance of difference led communities to live separate lives? Isolated from their neighbours and from the wider society.

"Lacking common bonds and mutual connections which could break down suspicion and misunderstanding.

"How far should we go in allowing special treatment for the ethnic, cultural and religious traditions of our communities?

"What are the limits to our tolerance and how might those limits be exercised? How do we deal with those who turn our tolerance against us?

"We need to have an open discussion as a party and as a wider society about who we are and what we believe in as Britons."

Speaking in the same debate, communities secretary Ruth Kelly agreed that "there are rules and values that have have to be understood and accepted by all groups, all races and all faiths".