State Pension
In the UK you must have paid National Insurance for 30 years, I believe, to be entitled for minimum state pension. State pension is earned in Spain by paying Social Seguridad for 5 years for minimum pension and 15 years for full state pension. You can obtain a higher state pension in either country by paying extra contributions. State pension can be claimed on top of your company pension when you have reached retirement age in your respective country although your tax will be adjusted to reflect you extra income.
No idea about the rest of Europe!