22/12/2016 07:02 GMT | Updated 23/12/2017 05:12 GMT

While We Celebrate Diversity Our Country Is Becoming Ever More Segregated via Getty Images

By 2035, almost 50% of Britons will be children or pensioners; by 2050, almost 40% of us will be Black, Asian or of mixed heritage.

Our diversity is something we rightly celebrate. As the Mayor of London, Sadiq Khan, has said, cities such as London are seen across the world as "beacons of tolerance, cohesion and integration".

But research just published by the charity I work for, The Challenge, has revealed how little we in Britain mix with one another - something I think should worry us all.

Our research - The British Integration Survey - shows Britons are socialising less with people from a different ethnicity to their own and finds that as a society we are becoming more segregated by ethnicity. Surprisingly, White Londoners are the least likely group to mix with people from a different ethnic background to themselves, while Londoners in general are less likely than those in other regions of the UK to socialise with those from a different ethnicity or age to themselves.

We asked 4,265 13 to 80-year-olds to tell us the most recent social event they had attended and to give the ages, ethnic background and job roles of up to five people they socialised with there. They were also asked to give where they lived, their age, ethnic background, job role and the nature of their relationship with the five people with whom they had socialised. The researchers calculated how many social interactions with other ethnicities might be likely using the census data on how ethnically mixed the area in which each respondent lived.

The researchers found that White Britons are least likely of all to socialise with other ethnic groups. Black Britons socialise with other Black Britons nearly eight times as much as the researchers would expect, while Asian Britons socialise with other Asian Britons more than five times as much as the researchers would expect. Worryingly, Britons of all ethnicities are socialising less with people from other ethnicities than in the past. The researchers, from the University of Oxford and University College London, compared the data to a comparable study of 4,235 people polled in 2014.

We celebrate our diversity, but we cannot reap the benefits of it if we fail to lead interconnected lives. We know that those who mix with people who are different to themselves have closer ties to their neighbourhoods and higher levels of trust.

We need to make many more opportunities - in schools, in the workplace and in our communities - to have meaningful contact with those from different walks of live to ourselves. That's why the charity I work for delivers programmes such as the National Citizen Service - it is here that teenagers meet others from very different backgrounds to themselves. We should focus on moments of transition. Starting school, becoming a young adult, starting your first job, settling in a new area, becoming a parent, retraining or retiring - it is during these moments of transition that we most want a new support group around us and when our identities are most in flux and open to new alliances.

Dame Louise Casey, the government's social integration tsar, published her review into integration only this month and her findings were stark, as they are for The British Integration Survey. While we celebrate our diversity, our country is becoming ever more segregated. Collectively and individually we need to take urgent steps to address this.