Birmingham and Hyndburn have been named as the UK's worst areas for food hygiene for the second year running.
They failed to come up to scratch across a range of areas including the number of high and medium-risk food businesses which keep to hygiene standards, the amount of premises which opened but were not visited or given a risk rating, as well as the number of interventions that had to be carried out, according to a study by Which?.
Birmingham City Council had a poor record for carrying out inspections within 28 days of a food business opening, with 16% of the city's more than 8,000 food businesses yet to be rated, according to the consumer group's report.
They also found that 43% of Birmingham's high and medium-risk food businesses did not meet food compliance standards.
Mark Croxford, of Birmingham City Council, said: "The quality of food businesses in Birmingham is not a measure or reflection of the council's performance.
"I am surprised and disappointed to see Which? have made the same mistake as they have done in previous years, in failing to engage with local authorities to produce a meaningful report.
"It is apparent - using the same LAEMS data available to Which? - that Birmingham City Council's environmental health team have inspected the second highest number of premises, undertaken more prosecutions, closed more food premises and suspended more approved manufacturers than any other English local authority in 2016/17.
"These interventions show we actively inspect food businesses and take any necessary action, where there are problems, to deal with them robustly and keep people safe."
He described the high number of new food businesses opening in Birmingham as "a significant challenge", stating that more than 1,000 new food businesses were registered in Birmingham in 2016/17.
Mr Croxford said "putting that into context, our officers have 8,341 premises to inspect across Birmingham, second only to Cornwall with 8,652".
Hyndburn Borough Council, the Lancashire region which counts Accrington as the biggest town, was the second worst area in the UK for food hygiene in 2016/17.
Which? said that 98% of its businesses had been rated for risk, but just two in five of its medium and high-risk food businesses met hygiene standards, compared with 98% in Harrogate, which is about an hour away in North Yorkshire.
Which? looked at data for 390 local authorities including information from the Local Authority Monitoring System (LAEMS), collected by the Food Standards Agency (FSA).
Erewash Borough Council, in East Derbyshire, was rated top for the second year in a row just ahead of Basingstoke and Deane Borough Council, in Hampshire.
Erewash carried out planned actions on all failing premises and 97% of its medium and high-risk establishments were compliant with hygiene standards.
Basingstoke and Deane could say that 96% of medium and high-risk premises met food compliance standards and 99% of food businesses were inspected and rated for risk.
Three Rivers District Council, in Hertfordshire, saw the biggest improvement between 2016/17 and the previous year. It jumped into the top 100 after being ranked among the worst 25% of areas in the previous study, Which? said.
The consumer champion also believes that Brexit could deliver another blow to standards. It states the Government, which is under pressure to safeguard current food standards, will need to step up checks on imports and potentially look to negotiate trade deals with countries with lower food standards.
Which? states there was one food hygiene enforcement officer per 403 food businesses amid a rising amount of complaints about hygiene and quality in 2016/17.
There has also been a 5.5% rise in the number of food premises yet to be rated compared with two years previously. This means that in 2016/17, 1,697 more businesses were running without a food hygiene rating compared to 2014/15, according to Which?
Alex Neill, of Which?, said: "When it comes to food, British consumers expect the very best standards for themselves and their families.
"But our enforcement regime is under huge strain, just as Brexit threatens to add to the responsibilities of struggling local authorities.
"Effective food enforcement must be a government priority, including robust checks on imports as well as co-operation with the EU and other countries on food risks".
Hyndburn Council's deputy leader Paul Cox dismissed the findings as "not a true reflection of the current picture in Hyndburn", saying the statistics used are 13 months out of date.
He said Hyndburn has since made a "big improvement" to 92.5% compliance, adding: "We've completed 100% of inspections for the past two years and our most recently submitted figures to the FSA for 17/18 shows the true picture that 92.5% of food businesses in Hyndburn are compliant in accordance with the Food Standards Agency food hygiene ratings scheme and only three businesses were unrated, but have since been rated within the permitted 28 days timescale.
"In the last few years we've taken significant strides to improve food hygiene performance and added additional resources to drive up compliance. We also took action against non-compliant premises which resulted in five voluntary closures, we also served 21 premises with food hygiene improvement notices and issued 301 written warnings."
He also pointed out that work continues in trying to ensure standards but "ultimately it is the responsibility of the food business operator to produce food which is safe to eat."
Councillor Simon Blackburn, chairman of the Local Government Association's safer and stronger communities board, said: "Councils work extremely hard to maintain and improve food hygiene standards, even as resources reduce, by combining reports and through collaboration which allows councils to share intelligence and avoid duplication of effort.
"Ultimately it is the responsibility of food businesses to ensure the products they produce and premises they serve from comply fully with food safety law and pose no risk, but councils continue to do everything possible to maintain checks in this area despite severe budgetary pressures."
The top 10 ranked local authorities are:
2. Basingstoke and Deane
4. North Dorset
5. South Kesteven
7. West Dorset
8. Staffordshire and Moorlands
10. Orkney Islands
Lowest 10 ranked local authorities are:
5. Isles of Scilly
10. Waltham Forest