The proportion of jobs outside London paying less than the Living Wage has increased to almost one in four, official figures have shown.
The figure for the capital has increased by 6% to 19% - well below the rest of the UK.
The Office for National Statistics (ONS) reported that the proportion of jobs paying less than the Living Wage outside London rose from 21% to 23% between April 2012 and April 2014.
The voluntary rates of £7.85 an hour outside London and £9.15 in the capital are due to be uprated next month.
Around 200 firms have agreed to pay the national Living Wage in recent months, with more expected to sign up before a new rate is set next month.
There are now more than 1,800 accredited Living Wage employers, ranging from leading banks such as Barclays, RBS and HSBC to small organisations employing a handful of staff.
The Living Wage Foundation sets the rate.
Accredited employers commit to paying staff at least the UK and London rates, as well as sub-contractors working on their premises.
New rates will be announced on November 2 at the start of Living Wage Week, likely to see the UK rate edge towards £8 an hour.
The figures are higher than the national Minimum Wage, which increased by 20p an hour to £6.70 this month, and compared with the national living wage announced by the Government of £7.20 which will come into force for over 25-year-olds next April.
Outside London, the area with the most jobs below the Living Wage was West Somerset (a total of 41.9%). The area with the fewest was Runnymede (8.5%).
Harrow had the highest number of jobs below the Living Wage in London (41.8%). The City of London had the fewest - just 5.2%.
The ONS report showed there were six million jobs in the UK paying less than the Living Wage in 2014, over half being part-time positions.
In the two years to April 2010 the proportion of jobs paying less than the Living Wage in London was stable at around 13%, but it rose to almost one in five by April 2014.
A spokesman for the Living Wage Foundation said: "Despite significant progress in many sectors, more jobs than ever are below the voluntary Living Wage rates that we recommend.
"These figures demonstrate that while the economy may be recovering as a whole, there is a real problem with ensuring everyone benefits, and low pay in still prevalent in Britain today.
"The best employers are not waiting for government to act. Around 1,800 responsible employers already pay the Living Wage to their staff. The Living Wage offers great benefits to business including reduction in turnover and higher productivity, while 70% of consumers say they would prefer to shop with a Living Wage employer."