Do you live above the bread, butter and jam line?

Discussion about poverty in Britain quickly gets snagged on the question of whether you can be poor if you have a plasma TV.

But if, instead of thinking about the breadline, we consider what level of income is needed for an acceptable standard of living, the debate changes.

It gives us a sense of what is decent in a rich country like ours, what we regard as a socially acceptable minimum.

It is not just about having bread - it's about having butter and, occasionally, a dollop of jam too.

The concept of a minimum income standard (MIS) was introduced by the Joseph Rowntree Foundation (JRF) four years ago - I wrote about it here.

Since then, of course, austerity has barged its way into our lives. So JRF decided to repeat the exercise of 2008 and see what's changed.

And the surprise is that so little has.

More than 20 panels of ordinary citizens were asked to put together a list of items they considered essential for an acceptable standard of living and the choices were very close to what their predecessors had selected four years earlier.

Family car

There were a few nods to belt-tightening: the budget for eating out and takeaways has been cut to £90 a year for a family of four; the current amount set aside for Christmas and birthday presents has been reduced; instead of swimming with a toddler once a week the panels made it once a month.

Back in 2008, the view was that people living in towns and cities could get by with public transport.

Now, though, the public panels have concluded that it makes more financial sense to use a second-hand hatch-back (1.6l petrol Ford Focus to be precise) - buying one that's five years old and selling at 10.

Rising public transport fares, cuts to bus services and the access to out-of-town discount stores a car allows, now make your own four wheels a necessity in all places except London.

On the roof of your Ford Focus, incidentally, you are expected to fit a storage box to accommodate supplies for a week's self-catering holiday in the UK.

No cigarettes or tobacco are on the list of needs, but a couple are permitted to buy four cans of lager and a bottle of red (keeps better than white) wine each week.

A TV is allowed - only Freeview, no cable or satellite contracts.

Mobile phones are now deemed a necessity, with the panels calculating it's cheaper to get one with an alarm clock and digital camera so you don't need to buy those items separately.

All families with children should have a computer with internet access.

When all the needs identified were added up, the minimum earnings for a family of four with both parents working worked out at just under £37,000 a year.

For a single working-age adult, minimum earnings would need to be £16,400.

That means more than a quarter of the population in Britain - 17 million people - don't have enough income to reach the level the public think is required for an acceptable living standard.

Those on benefits don't come close.

The minimum acceptable income calculated by the public panels is, in real terms, almost exactly the same as four years ago.

What has changed is that three million more people in Britain now don't have the money to meet it.