The UK's Olympic gold medallists are a prime case of how people from different races can unite under one banner, the only black woman Cabinet minister says.
The Olympics showed different races in British vests, says Amos
In a speech on Wednesday, Lady Amos also argues people are "reclaiming" the union jack from extremists as a symbol of different nations coming together.
The Lords leader says the UK has moved beyond being a multicultural society.
It is now a "multi-heritage society" where people from different backgrounds share common values, she argues.
'Winning back the flag'
The Labour peer, who arrived in Britain as a nine-year-old in the early 1960s, is delivering the Walter Rodney Lecture, organised by the Centre for Caribbean Studies.
She will say Team GB's story at the Olympics can be told through double gold winner Kelly Holmes, the victorious 4x100m relay team, Matthew Pinsent's fourth rowing gold and the shot to stardom of Bolton boxer Amir Khan.
"Mixed race, black, white and Asian. All drawn from different cultures and traditions and all competing in Britain's vest," she will say.
Amos says Britain has moved beyond multiculturalism
She will argue it is heartening that "decent people", whatever their colour, are reclaiming the union flag.
"I suspect that the ugly misappropriation of the flag by the extreme right and yobs in the past is responsible for the ambivalence felt by many proud, patriotic Britons," she will say.
But that is now changing, depriving the "extreme right" of a mask for their intolerant beliefs.
"As the country and its attitudes have changed - and as black and Asian people's contribution to modern Britain is increasingly recognised as an inseparable part of the whole - the flag should be a symbol of the coming together of different nations into one."
'No simple groupings'
Lady Amos says people and countries' identities are built up of several layers.
She, for example, is Guyanese-born but "African via the Caribbean", a woman who grew up in Kent and lived in London, who went to university and worked in local government, a peer and a Cabinet minister.
"We should be careful not to treat as a homogeneous group individuals who simply share the common experience of having a skin colour that marks them out as an ethnic minority," she will say.
The increased focus on race and religion in the wake of the 11 September terror attacks has seen strong debate in Britain.
Trevor Phillips, head of the Commission for Racial Equality, recently said the term "multiculturalism" should be scrapped because it suggested separate identities.
Entering that debate, Lady Amos will say: "We have gone beyond multiculturalism. Ours is a multi-heritage society...
"Yes, some can trace their heritage back to the Norman conquest. But others can trace theirs back to the Ashanti kingdoms of West Africa or to old civilisations on the Indian subcontinent."
She goes on: "My heritage matters to me but as important are the values I cherish and share with people whose background may be completely different to mine."
The peer also insists Labour can tackle "hate politics" by showing disaffected voters it wants to improve their lives.