http://en.wikipedia.org/wiki/Poverty_in_the_United_Kingdom
The definition of "poverty" in the UK is somewhat misleading - it is earning less than 60% of median income - so about £200 per week after tax , national insurance , rent / mortgage , council tax & water rates. Many people in other wealthy countries would love to have that kind of standard of living. By definition you will always have many millions "below the poverty line" and millions above. Labour admitted that much of their fiscal policy was aimed at moving as many people as possible just above this arbitrary line by tinkering with benefits and taxes. ( Off topic , but we had a service overseer who always used to say that "the society says that every publisher should be putting in "above average" hours". I often tried to explain to him that you would always get people who were below average , as the average would be raised if everyone did more , but he never got the point. )
I know many people living "in poverty" who nevertheless go abroad twice a year on holiday , have a good car , live in a lovely home , have an iphone4 etc.
As far as the UK being a 3rd world country , a bit harsh , methinks. While public debt is very high , we aren't quite the basket case that Greece , Portugal or even Ireland are. And we do have world leaders in some industries - notably defence , financial services & pharma. The public services can be poor , but still a lot better than many countries. Not too many earthquakes or tsunamis here , though we do get the odd ash cloud from Iceland's volcanos. All told , despite the weather , one of the best countries in the world in which to live.