Start retirement saving now or the UK government may make you

The spokesman said Morrisons supported government efforts to get people saving for retirement. "We have a large proportion of our employees in their 40s and 50s and we want them to work on voluntarily not because they can't afford to retire."

A manager at fashion retailer Next said: "I figured I'm 27 and should start some kind of pension so I haven't opted out," she told Reuters. But she also said would pull out if the contributions had a big impact on her monthly disposable income.

If Britain does make pension saving compulsory, it will join a long list of countries that have tried to cut their pensions bill in this way.

New Zealand's KiwiSaver plan, launched in 2007, takes contributions from the government, employers and staff and locks the savings away until people turn 65, but there are exceptions for those buying a first home or in cases of hardship.

In 2009, 35 percent of people were opting out of the New Zealand scheme but that has dropped to 6 percent in 2012, David Knox, senior partner of Mercer Consulting (Australia) Ltd, said.

Australia's government introduced a compulsory pension system in 1992 which set up state-supported superannuation funds, where employers are required to put in 9 percent of staff salary. That is due to increase to 12 percent by 2020.

"People in Australia and New Zealand are now more engaged with pension saving - there is general acceptance that you can't rely

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