Jack Straw told a constituency meeting in Blackburn he'd been "astonishingly blessed" to represent the town and work as minister and shadow minister but that at 67 he "couldn't guarantee" he could keep up the pace required into his mid-70's.
Althoughhe backed his brother David in the Labour leadership campaign in 2010, Mr Strawpaid tribute to Ed Miliband:
"In Ed Miliband we havea leader who has the ability, the determination, and thecharacter to take this country to a better, and much fairerplace than under this Government."
More top news
Shadow chancellor John McDonnell has backed a free vote for MPs on the issue.
Savers into the new scheme can expect rates as high as 4 per cent from some banks.
Very windy with gales possible