The Black vote and lessons learned from the US

The most recent census showed that the population under 18 is significantly more ethnically diverse than the rest of the electorate. This is filtering into the make-up of those who vote. Research published on Monday by Operation Black Vote (OBV) concludes that any future majority government will only be possible with the support of ethnic minority voters.

The Runnymede Trust's authoritative study of political integration and ethnic minority voting behaviour in the 2010 general election found that two out of three black, Asian and minority ethnic (BAME) voters supported Labour. Just one in six supported the Conservatives. These voters had the potential to decide 99 seats in England and Wales in the 2010 election. But OBV say this will reach 168 seats in 2015.

Whereas once political parties opted to tailor their policies to specific issues important to particular ethnic groups, it's now about the range of different paths that parties must take to expand their support base. The importance of getting on the right side of demographic change was seen in last year's US election. For the first time the turnout rate of "minority" voters exceeded that of white voters. While Mitt Romney won 60% of the white vote, this couldn't compensate for his failure to engage with minorities. As in the US, the British electorate has changed, and it is vital that our politics changes to reflect this.

This isn't about treating minority citizens as a bloc vote that automatically supports Labour. Their support must be earned. In fact, the level of support for Labour among ethnic minorities has been higher in the past. And the bad news for lazy politicians is that simply visiting a temple at Diwali, sharing a samosa at Eid or attending a community event in Black History Month won't be enough. Nor will relying on community elders or gatekeepers to deliver the vote. Minority ethnic issues need to be mainstream issues.

The surge in successful applications from minority ethnic communities for our Future Candidates Programme shows Labour's commitment. But having chaired Labour's inquiry into the Bradford West byelection defeat, it is clear that there are some parts of the country where politics is still letting down citizens.

An exciting discovery has been that minority ethnic votes aren't confined to inner cities or safe seats. They are spread around the country with significant numbers in seats key to Labour, the Conservatives and the Lib Dems. This means minority voters have never been more powerful and should demand more from political parties. I welcome an arms race for minority ethnic voters. This will ensure we all raise our game.

This year marked 45 years since Enoch Powell's "rivers of blood" speech on the consequences of immigration. As an electorate we've come a long way. Attitudes that were once acceptable are long gone. Events such as Stephen Lawrence's murder had a deep and lasting effect on society, not just particular ethnic groups.

The recent public backlash against the Home Office's "Go home or face arrest" campaign comes as a reminder that politicians can't single out and scapegoat ethnic groups in the way they were able to in the past without offending society as a whole. Bearing in mind the track record of the Conservative strategist Lynton Crosby – he was, after all, responsible for the Tories' "Are you thinking what we're thinking" posters in 2005 – it's curious that Conservatives think he will help them win over those voters at the next election they couldn't win over in 2010.

OBV's research confirms that if the Tory tactic was to ignore minority ethnic voters, that will no longer be possible. They are one among many groups that parties need to win over – yet perhaps now one of the most important.

Sadiq Khan MP

This article was first published in the Guardian