One has family roots in Pakistan, the other in Jamaica: the two leading contenders for mayor of multicultural London stand out amid an anguished debate about post-colonialism and race in Britain.

The office formerly held by Prime Minister Boris Johnson oversees a budget of ?17 billion ($24 billion, 20 billion euros) along with one of the world's biggest transport networks and city police forces, guaranteeing the mayor national exposure.

Opinion polls tip the Labour party's Sadiq Khan for a clear win on Thursday, five years after he took over from the Conservative Johnson, becoming Britain's best-known Muslim politician.

London Mayor Sadiq Khan, seen here on a campaign visit to Kingstonian Cricket Club last month, could win another term in office
London Mayor Sadiq Khan, seen here on a campaign visit to Kingstonian Cricket Club last month, could win another term in office AFP / Niklas HALLE'N

"The city back in 2016 chose me to be their mayor so it shows how progressive we are," Khan, the 50-year-old son of a Pakistani bus driver, told AFP.

"I'm really hopeful about the future, because I get to mentor and help some of those coming through the pipeline," he said.

"And there's a new generation of really talented British politicians coming through from different backgrounds, who I think will accelerate the progress in the future."

Boris Johnson back in 2015 when he was London mayor
Boris Johnson back in 2015 when he was London mayor GETTY IMAGES NORTH AMERICA / Craig Barritt

Khan's main opponent is the Conservative Shaun Bailey, 49, who like him grew up in social housing. Bailey notes that he would become one of Europe's most prominent black politicians if elected.

His grandfather emigrated from Jamaica in the late 1940s, part of the "Windrush" generation of Caribbean migrants who, along with South Asians, did much to rebuild London after World War II.

Shaun Bailey, the Conservative Party candidate for the London mayoral election, is Khan's biggest rival
Shaun Bailey, the Conservative Party candidate for the London mayoral election, is Khan's biggest rival AFP / JUSTIN TALLIS

In 2017, revelations that some in the Windrush generation had been illegally deported after living for years in Britain provoked soul-searching about racism.

The debate intensified last year with the "Black Lives Matter" protests as campaigners pressed for a new examination of the country's colonial past.

Independent candidate Count Binface is not expected to win the London mayoral race
Independent candidate Count Binface is not expected to win the London mayoral race AFP / Oli SCARFF

Bailey, however, is part of a new generation of minority Conservative politicians including finance minister Rishi Sunak and interior minister Priti Patel who play down race in politics.

"People are much more interested in my experience of London, and I have a unique one because of my background, but it's not the only thing I bring to the table," he told AFP.

Johnson's government has been leading an "anti-woke" agenda that seeks harsh new jail terms for vandalising statues of historical figures, following the toppling of a slaver's edifice in the western city of Bristol last year.

TV actor Laurence Fox is running on a libertarian platform
TV actor Laurence Fox is running on a libertarian platform AFP / Tolga Akmen

A government-commissioned report sparked outrage last month by saying that structural racism does not exist in Britain, prompting Johnson's most senior black adviser to quit.

The Conservatives stand accused by some critics of promoting a few visible faces in their ranks while doing little to address structural issues holding back minorities in education, housing, health and employment.

"On the surface it will look like it's making progress in terms of diversity," commented Dibyesh Anand, head of social sciences at the University of Westminster, stressing that political discourse is still focussed on the white majority.

In London at least, white Britons are in the minority, making up 45 percent of the city's population in the 2011 census, the lowest figure for any area in Britain.

The Conservatives' 2016 mayoral candidate Zac Goldsmith was accused of Islamophobia against Khan, who won comfortably.

Steven Fielding, professor of political history at the University of Nottingham, said it was "no surprise" that the Conservatives opted for a minority candidate after the controversies that dogged Goldsmith.

"It helps them maybe re-establish themselves as a more kind of liberal, inclusive party," he said.

"So it is evidence of a change of attitude. But how genuine is it in certain instances?"

Labour has also been shadowed by an anti-Semitism cloud under its former national leadership, which hurt its standing among Jewish voters in London at the last general election in December 2019.

But Bailey has himself been dogged by the emergence of years-old remarks questioning multiculturalism and the role of women.

Like other local elections around Britain, the London race was delayed by a year due to the coronavirus pandemic, and the leading candidates have been warring over jobs, housing and knife crime.

One of the minor candidates is TV actor Laurence Fox, running on an anti-woke and libertarian platform that has drawn accusations of racism, which he denies.

Fox is neck and neck in the polls, on a lowly one percent, with "Count Binface", a self-declared intergalactic space warrior.