CORONAVIRUS could affect parts of the country that combine severe deprivation, poor housing and large BAME communities, according to a leaked document that focuses on the north west.

Analysis by Public Health England which was sent to the Observer, and marked “official sensitive”, suggests the national lockdown in parts of the north had little effect in reducing the level of infections, and that in such communities it is now firmly established.

The analysis, prepared for local government leaders and health experts, relates specifically to the north west, where several local lockdowns have recently been put in place following a rise in cases.

But it suggests that the lessons could be applied nationally.

Based on detailed analysis of case numbers in different local areas, the study builds links between the highest concentrations of covid-19 and issues of deprivation, poor and crowded accommodation and ethnicity.

Produced in the last few weeks and containing data up to August, it states: “The overall analysis suggests Bolton, Manchester, Oldham and Rochdale never really left the epidemic phase – and that nine of the 10 boroughs (of Greater Manchester) are currently experiencing an epidemic phase.”

Four of the five worst-hit areas are all in the north-west.

Bolton had 98.1 cases per 100,000 people last week, with 56.8 in Blackburn and Darwen, 53.6 in Oldham and 46.7 in Salford.

The other area is Bradford with 63.2.

Comparing other English regions, the study says: “Each region has experienced its own epidemic journey with the north peaking later and the north-west, Yorkshire and Humber and East Midlands failing to return to a near zero covid status even during lockdown, unlike the other regions which have been able to return to a near pre-covid state.”

It also questions, under a heading marked for “discussion”, why anyone should expect fresh local lockdowns to work in these areas now

“If we accept the premise that in some areas the infection is now endemic – how does this change our strategy?

"If these areas were not able to attain near zero-Covid status during full lockdown, how realistic is it that we can expect current restriction escalations to work?”

The comments refer to tensions growing between Public Health England and the Government over the strategy to tackle local outbreaks as a potential second wave threatens.

Last night, Gabriel Scally, visiting professor of public health at the University of Bristol and a member of the independent Sage committee, described the findings of the leaked report as “extremely alarming” after being shown them by the Observer.

“The only way forward is to build a system which provides much better, more locally tailored responses,” Scally said.

“There is no integrated find, test, trace, isolate and support system at the moment.

"The data on housing is extraordinarily important. Overcrowded households are part of public health history.

"Housing conditions are so important and always have been, whether it was for cholera or tuberculosis or covid-19.

“Doing something about housing conditions for someone who has an active infection is extremely important and it is not something that can be handled by a call centre run by a commercial company hundreds of miles away.”

Scally said that helping people to isolate by giving financial support was also crucial: “Taking two weeks off if you are on a zero-hours contract is not an option for people.”

Last night, amid continuing confusion over rules on quarantining when returning to the UK, Labour called for a “rapid review” to restore public confidence.

In a letter to the home secretary, Labour is urging the government to consider introducing a “robust testing regime in airports” that could help to safely minimise the need for 14-day quarantine.