However, financial advisor Hargreaves Lansdown (HL) rejects bricks and mortar as a way of saving.

Says HL pensions analyst Laith Khalaf: “Holding one asset in one geographical region allows no diversification. Buy-to-let is more risky with a single property than for professionals with a portfolio of different areas and properties.

“People also see property as a certain bet, assuming prices always go up. In fact, there are significant costs and void periods and because few can afford to buy a second property for cash – you are paying monthly interest on your loan as you approach retirement.”

Laith Khalaf also points out that investors still in work pay tax at 20-40% on rental income, net of expenses and mortgage interest, while earnings on pension and ISAs are tax free.

An HL analysis points out that nearly 183,500 buy-to-let mortgages were taken out in 2007, near the height of the market, representing £23bn worth of debt.

Many of those investors are uncomfortable today: the value of their investment has crashed 20%, while monthly repayments could surge if rates rise.

David Lawrenson, a professional investor who writes a blog for fellow investors, sees a sector fragmented into two distinct groups.

Many who built a portfolio before the market peaked, with tracker mortgages which have plunged with base rate, may be building cash reserves for more investments.

By contrast, newcomers to the sector, looking to invest for retirement face a struggle: loan rates, after initial fixes expire, have soared, with arrangement fees as high as 3.5% of the loan.

“Until more lenders challenge the dominance of Nationwide BS and Lloyds Banking Group in this sector, new investors might wonder how the figures can be made to stack up,” says Mr Lawrenson.

But with the average age of first time buyers approaching 38, demand for private rented properties is soaring. The sector has grown from 2.1 million homes to 3.1 million since 2001.

In any market, the best time to buy is when few other buyers can bear to do the same. Only the brave or, perhaps, the reckless, would swear that moment has arrived in buy-to-let.

INFORMATION: Hargreaves Lansdown (0117 900 9000 and www.H-L.co.uk); Charcol (0800 718191 and charcol.com); David Lawrenson’s book, Successful Property Letting has sold 23,000 copies since September 2005 (www.LettingFocus.co.uk and 0208 690 3138) and his seminars for would-be property investors cost £30.