So what exactly is the Lifetime Isa?

The scheme is open to Britons aged between 18 and 39, who can save up to £4,000 a year and get a 25 per cent bonus on the money they pay in. So if they save the maximum they can get a top-up worth a generous £1,000.

Once you have opened an account you can keep claiming that bonus on money you pay in until age 50. Somebody who opened a Lifetime Isa on their 18th birthday and contributed the maximum £4,000 every single year until age 50 would get a total bonus of £32,000, at least under current rules.

The Lisa comes as part of your overall £20,000 individual savings account (Isa) allowance, rather than on top.

Sadly, if you were born either on or before 7 April 1977, you do not qualify but should alert younger family members.

One reason so few people seem to know about the Lifetime Isa is that it has only just launched, and choice has been limited.

Only investment platforms Hargreaves Lansdown, Nutmeg and The Share Centre offered an investment Lisa at launch, although AJ Bell, Fidelity and Charles Stanley Direct have indicated they will follow.

Another downside is that the rules are complicated. Savers can only put the money towards their first home, which cannot cost more than £250,000, or £450,000 in London.

You are disqualified if you have ever owned a property before, even a part share of an inherited property inside or outside the UK, and cannot use it for an investment property.

However, you can still claim the cash and use the Lisa to fund your retirement, provided you don’t touch your pot until age 60. If you do, you will lose a stinging 25 per cent in exit penalties, as the government wants to encourage long-term savings.

Read more: How to be an ISA millionaire

Another reason many people are confused is that Isas have got complicated in recent years, with six versions now on offer.

You can also choose from Cash Isas and Stocks and Shares Isas, the new Innovative Finance Isa, the Junior Isa and the Help to Buy Isa, as well as the Lifetime Isa.

It is worth spending a little time working out whether this works for you because it isn't every day the government offers you £1,000 a year for free. You could call it a once-in-a-lifetime opportunity.