Total unemployment in the UK is currently 4.78 million, close to double the headline unemployment figure, a Trades Union Congress (TUC) analysis has warned.
The latest analysis, which belies the government's optimism about the state of the economy, comes as the TUC meets for its annual conference from 8-11 September in Bournemouth, southern England.
Women are particularly badly affected, with total female unemployment more than double the headline unemployment measure, says the TUC.
Headline unemployment in the UK, which is defined by the International Labour Organisation as those who have sought work within the last four weeks, are available to start in the next two weeks or have accepted a job that they are yet to start, is currently 2.51 million.
But TUC analysis of official figures shows that unemployment is actually far higher once wider measures of joblessness are included. A further 2.26 million people in the UK want a job but are not classified as unemployed. In the US this group are described as 'discouraged' workers or economically inactive people who want work.
Total unemployment (called U5 unemployment in the US) in the UK is 4.78 million U6 unemployment, another measure of unemployment in the US that includes part-time workers who want more in their current jobs - known as under-employment in the UK - is currently 6.2 million in the UK.
The TUC analysis shows that total unemployment for women (2.42 million) is more than twice the size of headline unemployment (1.07 million). Total unemployment for men (2.36 million) is 64 per cent higher than headline unemployment (1.48 million).
Total unemployment in the UK is 945,000 higher than its pre-recession level of 3.83 million in January 2008.
The TUC believes that wider forms of unemployment should be given the same level of importance in the UK as they are across the Atlantic. Total (or U5) unemployment gives a more thorough picture of joblessness across the UK, while U6 unemployment also highlights weaknesses in the labour market such as under-employment.
With the Bank of England now paying closer attention to labour market performance when setting monetary policy, it is important that officials get a more detailed picture of the true strength of the UK's jobs market, says the TUC.
The TUC analysis has been published ahead of the TUC's 145th annual Congress, starting today (8 September).
Under-employment and vulnerable work will be one of the topics for debate during the four-day Congress.
TUC General Secretary Frances O'Grady will set out her vision for a stronger and more sustainable recovery, in which the creation of high-quality jobs and decent pay rises play a central role, in her address to Congress on Monday morning, 9 September.
In her pre-Congress press conference, Ms O'Grady declared: "Unemployment may have started to fall in recent months but we are still in the midst of a job crisis."
She continued: "The true scale of unemployment is far bigger than official figures suggest, as nearly five million people say they want work today. With a further 1.4 million people only able to find part-time work, despite needing a full-time job to get by, it's clear that our labour market remains far from full health."
"With the Bank of England now focused on unemployment, it's important that official figures better reflect the true nature of the jobs market. We know that the recent fall in unemployment has been driven by short hours, low pay, temporary contracts, and jobs that offer no guarantee of paid work at all. These types of jobs cannot form the basis for a secure and sustainable economic recovery," said the TUC chief.
"We also need ministers to face up to people's concerns about under-employment and insecure, low-paid work, which they have so far failed to acknowledge even exist. Unless we start getting more high-quality jobs and decent pay rises, this recovery is going to feel pretty joyless to most people," Ms O'Grady concluded.
* TUC: http://www.tuc.org.uk/
* Descriptions of the six measures of US unemployment (U1-U6) are as follows - U1: Persons unemployed for 15 weeks or longer; U2: Job losers and persons who completed temporary jobs; U3: Total unemployed (official ILO unemployment rate); U4: Total unemployed plus discouraged workers; U5: Total unemployed, plus discouraged workers, plus all other persons marginally attached to the labour market; U6: Total unemployed, plus all persons marginally attached to the labour market, plus total employed part time for economic reasons