Workers on the bottom rung of the earnings ladder received a leg up on Saturday, as the national minimum wage increased from £5.98 to £6.08. But new research shows that as many as 5 million people higher up the scale are barely earning enough to make ends meet.
Thinktank the Resolution Foundation has looked at workers up and down the country earning less than a "living wage". It found that more than one in five employees falls into this group, echoing recent work by the TUC, which uncovered what it called a "livelihood crisis" among the growing swathe of the workforce stuck in low-paid jobs.
In London, there is an official "living wage" endorsed by the mayor, Boris Johnson, and currently set at £8.30 an hour. It's intended to be the least amount required to pay for what most people consider to be basic necessities and a "minimum acceptable quality of life".
Loughborough University's Centre for Research in Social Policy, considered the authority on the issue, calculates that outside the capital, you need £7.20 an hour.
Using official earnings figures, Resolution finds that in some parts of the country, almost a quarter of the workforce are taking home less than this. They range across a wide range of sectors, from sales, where 60% of workers earn less than the living wage, to personal services such as hairdressers and childminders (33%).
"It brings to life just how pervasive low pay is in modern Britain," says Resolution's chief executive, Gavin Kelly. "Many people on higher incomes would assume it only exists on the fringes, not the mainstream."
Instead of being a short-term result of the recession of 2008-09 and the lacklustre recovery, Kelly sees the increasing problem of low pay as being the result of a long period when the fruits of economic expansion failed to feed through to those at the bottom of the pile. "It shows you what it looks like after a long period of growth, and it makes you raise questions about the nature of that growth and who it benefited," he says.
Resolution's report says: "Historically, periods of economic growth have led to growing wages for ordinary workers, ensuring rising living standards for all households. But this connection between growth and gain for workers has started to fray in recent years."
Nicola Smith, head of economics and social affairs development at the TUC, says structural changes, such as the decline of the manufacturing sector, have hollowed out the skilled-jobs sector that once made up a large proportion of the workforce, resulting in a polarisation between high-paying "knowledge economy" jobs, monopolised by graduates, and a "long tail" of lower-skilled workers struggling to get by.
"Over the past decade, there's been a loss of about 1.5m jobs in manufacturing," she says. Meanwhile, a long period of rapid expansion in highly paid industries such as banking, and the increasing prevalence of share awards and bonus payments, helped earnings at the top of the scale to race away from the rest.
Resolution's research shows that low-paid workers are disproportionately female, part-time, and concentrated in the private sector.
Smith says that could mean the number of low-paid jobs will increase as government cuts bite: "The public sector has until now played a large role in creating middle-income jobs for people with skills."
Recent research by the TUC showed that the erosion of living standards for lower-paid workers is a very long-term phenomenon: while incomes for the top 10% of earners doubled in real terms between 1978 and 2008, they increased by just 27% for the bottom tenth.
Whether they are called the "squeezed middle", "hard-working families" or the "deserving poor", there is little agreement about what to do to improve their lot – and politicians are divided about how to win their support.
Liberal Democrats are proud of persuading the Tories to adopt their policy of raising the personal income tax allowance, which helps to take the lowest-paid out of tax altogether.
However, the increase in the allowance also benefits many earners higher up the income scale, causing some analysts, such as the Institute for Public Policy Research (IPPR), to warn that it is badly targeted.
There are also fears that a series of changes to the tax and benefits system introduced by George Osborne and Iain Duncan Smith, including the reduction in the childcare element of the working tax credit, could act against the increase in the allowance, and make life harder.
Ed Miliband's speech to the Labour party conference suggested that he takes a top-down approach to the issue, advocating putting workers' representatives on companies' remuneration committees to argue the case for fairer pay and helping to rein in excessive rewards at the top.
Smith says the government must also think about ways to encourage key sectors, such as the sciences and creative industries, which employ relatively large numbers of more skilled workers. "It's the challenge of creating better quality jobs," she says.
A more direct approach is bottom-up agitation. In the capital, the Living Wage campaign, run by London Citizens, a coalition of religious leaders, community activists and trades unionists, was launched a decade ago to highlight the plight of many workers doing jobs essential to the smooth running of London.
An army of cleaners, drivers, shop-workers and so on, many of them migrant workers, were unable to earn enough to afford to eat decent food, keep a roof over their heads, or spend any time with their families.
"You're talking about people getting up at 4am to get two night buses to work, and sending money back to their families in Ghana," says Andy Hull of the IPPR, who is involved in London Citizens.
London Citizens has used the full battery of campaigning tactics, including noisily invading the offices of Goldman Sachs, and tabling questions at HSBC's annual meetings, to persuade employers to pay their staff more generously, and offer longer-term contracts.
Hull says: "You need the top-down and the bottom-up; you need to apply pressure." London Citizens has a meeting with Tesco on Wednesday, in its latest attempt to persuade the mega-retailer to extend the relatively generous wages that it pays its shopfloor staff to thousands of sub-contracted cleaners, security guards and delivery drivers. "At least a dialogue is happening," Hull says.
He adds: "The argument that no one should do a day's work for less than a wage they can live on is a hard one to disagree with."