BBC Radio 4's Money Box was broadcast on Saturday, 22 January, 2005, at 1204 GMT.
The programme was repeated on Sunday, 23 January, 2005, at 2102 GMT.
The government is writing to half a million pensioners telling them they can boost their pension if they pay extra National Insurance contributions.
The letters are being sent to put right a mistake made in 1996 when the government stopped telling people the state of their National Insurance account.
As a result many people who could have paid extra then, did not do so.
Now they can. But the four page letter has been criticised as hard to understand.
We heard from one pensioner who has received such a letter, and spoke to her local MP, Liberal Democrat pensions spokesman Steve Webb, and Gary Vaux of Hertfordshire County Council's Money Advice Unit.
Presenter: Paul Lewis
Producer: Jessica Dunbar
Reporter: Samantha Washington