MPs have staging a second revolt against the Welfare Reform and Pensions bill, putting the stakeholder launch date in further jeopardy.
The Government's majority was slashed to 60 from 177 after MPs voted against a controversial cut in disability benefit, which is part of the bill.
The bill returns to the House of Lords on Monday.
Social security secretary Alistair Darling is expected to be forced to make dramatic concessions if the bill is to be voted through by the Lords.
The stakeholder has to be passed through as law before providers can formally draw up product plans for the stakeholder launch, planned for April 2001.