Your pension income will be a sum of your state pension and the income from your private/occupational pensions. The state pension when you retire will depend on the financial situation of the country at the time. There are Government talks at the moment about a rate of £140 a week, but your pension will be dependent on what the country can afford at the time.
Your private and occupational income will be dictated by the size of your combined pension pot and the annuity rate you are able to obtain at the time. Annuities are bought from an insurance provider and essentially turn your pension pot into a lump sum payment, often of 25%, and an income for the rest of your life. There are other options available pre the age of 75, such as income drawdown, and hybrid investment/annuity products. When it comes to retirement you should seek financial advice as the first annuity offered to you will be unlikely to be your best pension income option.
Your annual pension statements will give you an indication of the real value of your pension on retirement, having factored in the effects of inflation. This is designed to tell you what your money will buy when you retire rather than what the money will buy in todays marketplace.