A few years ago a communications team from the Slough PCT identified a problem with Sikhs. Very few of them were presenting at a screening service for checking early stages of diabetes.

Slough has one of the largest Sikh communities in Britain so a campaign was launched. After early failures a communications centre was set up in the car park of a large Sainsbury’s supermarket, but to no avail. It was explained to the team that shame would accrue to Sikh men who were found to be diabetic and that the only way to overcome this shame would be for the elders of the community to join the campaign in support of the screening centre.

This is an example of the importance of ethnic understanding in the design of a public communications campaign. Without it the Sikh community would have been under-represented in diabetes screening, a public service for all UK residents. However, all too often public sector bodies are too scared of being branded racist to use ethnicity as a way of effectively and fairly delivering their services.

The recent government commissioned report into minority integration in the UK by Dame Louise Casey, which sparked mass media debate, has highlighted this very fact. The report revealed that decision makers were ducking important issues, such as the isolation of women in some Muslim communities, out of a desire to respect the practices of different cultures.

And herein lies the problem as soon as the thorny issue of ethnicity rears its ugly head the overwhelming instinct is to turn a blind eye rather than risk being accused of discrimination – whether on the scale of tackling segregation or smaller issues such as identifying minorities that are underrepresented in health screenings.

In places such as Slough building links with minority leaders is now a critical task of police forces, health authorities, social services teams, planners, housing departments and electoral registration officers. In Slough such links are effective because Sikhs are a large and coherent community in the town.

But what of Wood Green or Walthamstow? Here you find a melting pot of different communities, but unlike the Sikh community in Slough they are seldom reachable by local leaders. If you live in Wood Green you are obliged to speak English since no individual minority is large enough to dominant the community. Everyone must get along with members of other communities, to communicate English and to adjust to life in a melting pot without the security of existing in a ‘parallel universe’.

To help local authorities map out the different strategies they may need to adopt to tackle social cohesion, Big Data has been used to identify the level of diversity in 2016 in every street in Britain. Using the names of 50 million adults, analysed at the level of the unit postcode (eg N6 6DJ) an algorithm predicts the probability that two adults, taken at random from the postcode, will belong to different minority communities. A high score on this measure occurs in places such as Wood Green where streets typically contain members of many different minorities. Low scores occur in places such as Southall which are dominated by a single ethnic minority group.

The eight local authorities whose streets, on average, are the most diverse and where it is therefore most difficult to identify minority community leaders are all in London. The ten where streets tend to be dominated by a single (non-white British) minority are in the Midlands and either side of the Pennines. Life as a member of the minority population is very different depending in which of these authorities you live in.

Clearly in the London group there are serious risks of inter-communal tensions but there is little evidence of conflict with the host community, which is largely absent. At the opposite end of the scale are communities many of whose members can live in a parallel universe, which have strong internal links, but poor connectivity with outsiders.

In Derby, which is typical of many authorities that contain a mixture of mono-cultural and melting pot streets, the older-established inner city in which immigrants first settled remain the most diverse.

However, it is the more suburban locations to which immigrants have more recently where community leaders are easier to locate but where hidden problems of segregation as outlined by Dame Casey’s report are most likely to occur. Contrary to what had been assumed, the more prosperous members of minority communities are tending not to move to live in white neighbourhoods, but to move to communities of this sort, which are physically separated from members of other minority communities.

It is such granular understanding that will enable public sector bodies to adopt the policies set out in Dame Casey’s Review and to deliver services to minorities in a more effective but fair manner.

Table: local authorities with high and low levels of diversity at postcode level

Professor Richard Webber is co-founder of Webber Phillips.