Think you're middle class? You may well be mistaken

This would mean a weekly salary of about 640 a week for the average family after tax, according to new research.

The majority of people in the UK appear to believe that they are "in the middle" of the income distribution chain. This includes poorer people in the bottom third of the income distribution, up to people in the top five or ten per cent.

However, figures from the Institute of Fiscal Studies (IFS) indicate that many are nowhere near this area.

Researcher Luke Sibieta said: "When you ask people generally they think they're near the middle, but not everyone can be.

"There's probably quite a lot of people there who are poorer than they think they are and quite a few people who are richer than they realise they are."

The economic downturn would appear to have had little impact on what it takes to qualify as a Middle Briton.

"The curious thing about the recession is that most people who didn't lose their jobs saw their incomes carry on growing," Mr Sibieta added.

"It was just after the recession that people's living standards were hit quite a lot."

The IFS said the official poverty line was anyone earning less than 60 per cent of the Middle Britain figure. Some 17 per cent of households fall into this category.

These include couples with two children with net incomes of less than 380 per week, and lone parents with two children whose net incomes are less than 300 per week.

It would also include pensioner couples with weekly net incomes of less than about 250 per week.

An extra 750,000 earners were drawn into the 40 per cent income tax rate when this fell to 42,475 in April this year.

The IFS has created an iPhone application that allows families to see where they stand in the national pecking order in terms of their annual income.

The think-tank said there was a small group of "super-wealthy" that have a gross annual income of at least 2.5 million. But the richest 1 per cent will be earning more than 224,000 a year, which works out as a weekly take-home pay of 2,400.

The richest 10 per cent of earners includes some on more modest incomes. A couple with no children where each earns 30,000 a year before tax, giving them a weekly net income of 840, would just make it into this category.

However, a family with two children who fall into the Middle Briton category will typically have a weekly income, after tax, of about 640.

Middle Britons would equate to having a single earner in the family on 45,000 a year before tax, or two working adults with each on 20,000 a year.

A couple with no children would need a weekly net income of 420 - the equivalent of a single earner on 30,000 before tax or two adults each earning 14,000.

This group would also include a pensioner couple with a net income of 420 a week.