Up to one in three workers in some parts of the country will receive a pay rise when the new national living wage comes into effect on Friday, a new study has revealed.
Torridge in Devon, Rossendale in Lancashire, Woking in Surrey and Castle Point in Essex were named as the areas most likely to benefit from the £7.20 an hour rate for adults.
The Resolution Foundation said employers in these areas will see "significant" increases in their wage bill.
The new rate will have less impact in London and the South East, with just 3% of workers in the City set to have a wage rise on Friday, which the think tank said reinforced the importance of the voluntary living wage of £9.40 an hour in the capital and £8.25 in the rest of the country.
The biggest city to benefit is Sheffield, where over a fifth of employees will qualify for the higher wage, said the report.
Across Britain, one in six employees will be affected by the national living wage, with a total of 4.5 million people having an increase on Friday.
Torsten Bell, director of the Resolution Foundation, said: "The national living wage is a hugely ambitious policy with the potential to transform Britain's low pay landscape. Up to a third of workers will get a pay rise in national living wage hotspots, ranging from Canvey Island to Eastern Lancashire.
"Britain's new legal wage floor will be felt throughout the country, but its impact will be bigger in some areas than others. Relatively few employees will benefit in high-paying parts of Britain such as the City of London and Camden, reminding us of the need to see more employers sign up to pay the higher voluntary living wage.
"Of course pay rises don't come free so employers in some sectors and parts of the country will feel the pressure more than others. That's why it's vital that businesses and national, regional and local government make the successful implementation of the new legal minimum a priority."