By Paul Lewis
BBC Radio 4's Money Box
The man in charge of implementing the government's new national pension plan says it may be delayed.
Tim Jones suggests that the name "personal accounts" may change
The new scheme, personal accounts, was due to start in April 2012.
But Tim Jones, chief executive of the Personal Accounts Delivery Authority, says there is a "possibility" the date will slip.
He also said contributions would be cut from 4% to 1% of pay in the first year for the five million people he predicts will join.
How it works
When the new pensions regime begins, everyone in work will automatically be enrolled in a work based pension - either an existing scheme or one of the new personal accounts.
People can opt out, but if they do they will be opted back in every three years and when they change jobs.
Contributions into the scheme will be paid by the employer and the employee.
Eventually these will be 8% of a band of earnings between about £5,000 and £33,500.
Employers will pay 3%, workers will pay 4% and 1% will come from tax relief.
The government has already announced that the firm's share will be phased in over three years at 1%, 2% and 3%.
But speaking on Radio 4's Money Box programme, Tim Jones revealed that the individuals' contributions would also be phased in, starting at 1% in the first year.
The Department for Work and Pensions confirmed that the 4% contribution would be phased in over three years.
A spokesman told Money Box: "The government is looking at the simplest way of phasing it in over the same period and in whole numbers.
"So after tax relief it could, for example, be 1%, 2%, then 4% in year three.
"But that is not decided yet."
Tim Jones also warned that the target date of 2012 might not be achievable.
"The honest answer is I do not know yet.
"As incoming CEO it makes sense for me to review the plans.
"I understand the desire for 2012 and so far I have not seen anything that says it is unachievable, but what is critically important is not exactly when it starts, but that it starts well."
When pressed if he might tell the government it would have to be later than 2012 he replied, "There is that possibility yes."
Tim Jones also confirmed that the name "personal accounts" was being reviewed, as it did not explain what the new scheme did.
He stressed no decision had been made, but added:
"If you want Tim Jones' hunch then [my] hunch is it will not be called personal accounts when it eventually comes through."
BBC Radio 4's Money Box was broadcast on Saturday, 29 December 2007 at 1204 GMT.