Since it was abolished by Mrs Thatcher in 1980, campaigners have battled for the link to be brought back. If it had not been scrapped, the basic state pension would now be £158.60 instead of its current £97.65.
Yesterday in an exclusive webchat with Saga magazine, Mr Brown pledged that the link would be restored in 2012.
The Commission into pensions led by Lord Turner made this its top priority when it reported four years ago but the government resisted accepting the recommendation because of its high cost – well in excess of £1 billion a year.
All three main parties have subsequently said they wanted to restore the link but this is the first time Mr Brown has made an unequivocal commitment for a future Labour government..
Said Saga's Paul Green: "All the parties have pledged to restore the link but this is the first time in this election campaign that firm timings have been given. Britain's pensioners have been oft-promised but
undelivered. It's a clear indication that the Saga Generation is such a crucial constituency to woo that the election campaign will be fought on fields of silver."
See the full Saga webchat at www.sagatv.co.uk.