jake the peg mentions an aging population. This is probably the biggest problem facing the UK today (and many other western countries).
If you look at this picture it shows the population pyramid for 3 countries:
http://www.uni.edu/gai/India/India_Lesson_Plan s/India_Population_Pyramids_files/image002.gif
Kenya on the left has a HUGE young population (wide at the base), with the population narrowing the older they get.
This means there are plenty of young people to look after (and pay for) the few old people.
The USA in the middle has a reasonalble number of young people, but has many middle aged and older people, and could have a problem in a few years time.
Germany on the right (probably like the UK) has a real problem because the birthrate is low, and has a huge number of people born in the 1950s and 1960s who will be "old" people in 20 years time, but just not enough young people to look after them (and pay for them).
Immigration has been encourage to try to reverse the situation (birthrate higher amongst immigrants) but has brought with it huge other problems such as issues of race, religion, crime, inner city slums and so on.
I am afraid overall it does not look good for our future and I would encourage you to get out now while you can.