We've seen much over recent weeks about how awful the City has been. How banks have made rash dodgy loans. Short sellers, overpaid executives and whatever else...

But I'll let you into a little secret: for every loan there is both a lender, perhaps a dodgy spiv with too high a bonus to be sure, but just as importantly there has also to be a borrower.

We have seen a little po-faced political bemoaning of the culture of consumer debt, but this unsecured credit - spending money - does not appear to be the primary debt that has caused this collapse. With few exceptions, when the banks talk about the sub-prime loans lying like a half-dead half-back at the base of a maul, they are talking about mortgages. Are not these borrowers to be condemned in equal proportion? Did the bankers force them to borrow? Are not they just as greedy, in their own way, as the bankers making themselves rich on those borrowers' seeming insatiable demands for more money? Maybe these are the real "sub-prime loons" that are really responsible for bringing our economies near to systemic collapse?

Of course it would be electoral suicide to lay so much blame on the ordinary "Joe Sixpack, the hockey mom". And indeed it would be quite wrong to do so. For most of those mortgage borrowers, perhaps especially what has become known, horribly disparagingly, as the "sub-prime" borrowers, were being completely rational. Rational, that is, in an utterly irrational system. And the results of that rational behaviour are now serving to highlight just how irrational the system is.

Indeed, it is so utterly irrational a system that those borrowers we might want instinctively accuse of being the least rational - those whose chances of paying off the large loans were the smallest - are in fact the most rational. Because in that mad upward spiral of house prices, those still left renting would be the worst hit. The urgency of getting out of renting and fixing your future housing costs at today's rates is all the more pressing.

Because here's the second little secret for tonight: we all rent.

This may seem counter-intuitive in a world where 70% of folk "own" their home and most of the rest want to. If you are, or can recall when you were, on the point of making the transition from renting to buying the first time, this will be easier to understand. One of the factors in your decision to stop renting and to buy instead will have been whether the mortgage payments, as compared with your current rent payments, are reasonable value, over the length of time you expect to be needing to use that property.

Of course there are many other factors as well. Some in favour of ownership, such as being able to improve, redecorate or even trash the property, and having the prospect of capital growth. Some in favour of renting, such as not being responsible for all the maintenance, or not being stuck with a mill stone if you can't sell it when you need to move. And of course the supreme benefits: a. you don't need to charge yourself rent - after all you are paying for it anyway and b. if you get to the end of your payments okay, you get it rent free for as long as you like and still get to sell the rights to it hopefully at a tidy profit.

But as tradable assets, our properties are valued on the basis of the yield it could achieve to an investment buyer now, and their view of how that is going to change over the time they expect to hold the investment. And when we buy a home, what we are actually buying is the right to collect the rent on that property for several years ahead at a "fixed" price today that we think will benefit us. Few owner occupier buyers will probably think about it that clinically. They might instead look at local comparisons to assess what they ought to be willing to pay. But so long as there is a rental market, and since there are some disbenefits to ownership as noted above it is likely that there will always remain a rental market, the money-value to the market is going to be based on its current and future rental potential and the overall yield over the time an investor would expect to hold that property investment.

So, what rising house prices indicate is that investors believe that there are going to be higher returns in terms of future rent potential. And if you are still a tenant, higher returns to the landlord mean higher costs to you. So if it is economic to freeze the rent payments at or near today's levels for the foreseeable future, you definitely want to do so. This becomes a bubble because the effect of future expectations compounds itself. Throw in relatively cheap loans and people can afford more in the present to secure those expected future gains.

Okay, now having, I hope, got you thinking in terms of "rent" I want to get you thinking about the different components of this "rent".

Take two identical, some might call them identikit, homes. Two same model "Barratt boxes". Only one is in Kensington & Chelsea, the other in Blaenau Gwent. I choose them because they are the highest and the lowest respectively local authorities by "land value" in England and Wales. Three bedroom, 100 sq m and with a rebuild cost of £1500 per sq m. On the face of it, they ought to cost about the same to buy, somewhere around £150,000, but of course they don't, do they.

If you managed to find the same little plot in K&C as in Blaenau on which to place your "Barratt box" you'd probably find that in Blaenau it would cost next to nothing - probably a couple of thousand pound per plot, for the trouble of clearing it! But in K&C it would cost several million and probably wouldn't be worth your while putting that Barratt box on it! In fact, in the recent purchase of Chelsea Barracks by the Candy brothers, which was reported as £959m for 12.8 acres, your average tenth of an acre plot would set you back a cool £7.3 million.

In fact, the Chelsea Barracks site is a good one to look at, since it will not involve criticizing the "poor widow" for not developing her prime land, but the government! What did the government, the Ministry of Defence do to make that barracks land so valuable? It certainly wasn't its former use as a barracks! It's not because it was a barracks that makes it an in demand site. But because of all the economic and social activity that goes on around the site. In fact, once upon a time, as a barracks, no doubt the site would have attracted the usual motley collection of military hangers on - whore-houses, bars and so on - it may even have depressed local land values initially, but certainly for the past few decades holding it out of its more productive use has meant other local prices have been pushed higher than they would be if all that land had been used productively.

In fact, the proportion of the "rent" due to the value of the building, the same sort of building as in Blaenau, is a tiny fraction of the overall rent. The rest is due to the location. The popularity of a location which is made up of dozens of factors, but centres around the fact that there are hundreds, thousands, of people who could beneficially make use of that location to be nearer work, social and other opportunities created by the surrounding community.

Now, here's the easy part to remember. What Land Value Taxers want to see, from David Ricardo, Adam Smith, J S Mill, Henry George to Lloyd-George, Churchill, Asquith and many others to the present day, is that the portion of the rent a property yields due to its location, and not the building on it, should be collected by the community and redistributed amongst the community instead of privatised by the highest bidder (or in some cases still the person with the most brutal land grabbing ancestor!), shored up by cheap bank loans. It is rent due to its monopoly as a good location that many people could make use of rather than any effort of the landowner.

In an LVT based tax system, when you "buy" your home, you'd be buying the right to collect the rent for the building alone. This is something you as an owner can affect, through your diligence or negligence in maintaining it or in building something of higher density on the same site. In the language that a typical home buyer will understand better, we want you to pay the £150,000 for the Barratt box to Barratt or the previous occupier, but you pay the remainder, the rent caused by its location, in annually assessed chunks, to the state instead of paying taxes on the earnings from your economically productive labour.

You can already, I hope, see the advantages. This bubble we have lived through over the past decade, the angst of people priced out of the market stressing about if they ever will get out of renting, the ballooning of borrowing that now threatens the very system that created it, will be things of the past. For as long as you can justify paying the location rent given the benefits that particular location gives you nobody can shift you. If that rent rises it is a sign that more and more people are being excluded from land that they might make more productive use of than you. Why should you be able to exclude them for as long as you like and then also reap a massive profit from having cost so many others much money "avoiding" your plot?

Instead of that home in Kensington & Chelsea costing you £7.35 million up front, it'll cost you £150,000 or so up front, which you can borrow to pay for if you need to, and a hefty annual location rent bill instead of both the remaining £7.2 m mortgage it would have cost you to buy the location up front and your income and other taxes on productive labour. Your disposable income is likely to be maybe 30% higher just for losing those income taxes. You can save in a wider range of productive assets for your future than just the monopolistic endeavour of owning a popular, or up and coming location. You may even choose to save so you can continue to pay the location rent when you stop earning for whatever reason - though most would probably find it just as good to save for an income in retirement and to downsize or move so that someone else can have the benefit of the local school you no longer use, the local rail station you no longer commute from and whatever other factors have made your location a popular one and for the proximity of which you would continue to pay even after you have stopped using them.

In the lingo, this is called creating "free land". Returning it to common ownership and paying as you go to occupy the bit that most suits you at any particular time of your life.

Even apart from the source of government revenue this would provide (though some of us would prefer to see the rent collected and simply doled out to all citizens in that community as a community dividend, a basic universal non-withdrawable income in place of most cash benefits) it fundamentally shifts the burden away from working and producing and onto inefficient use of scarce resources.

It is essential in an environmentally responsible regime, because it makes the choice of whether to live close and not pollute by commuting or to live far and spend a fortune in travel costs, more available to more people.

And it is essential in a liberal regime, as it gives people a choice in the "taxes" they pay - the tax savvy will soon work out that if they can spot an up and coming area that still meets their needs early they will pay less tax and watch the services there get better as others catch on, until it reaches some kind of equilibrium again. And it stop people making monopoly profits out of excluding others from what we all need access to - a location to base ourselves at.

This would be so much more than just a "tax switch" though - it would so fundamentally change the fairness, equit, economic justice for millions of people who, knowingly or not, are trapped in a system that takes money from them to line the pockets of landowners, the ranks of whom are getting ever more distant for many people all the time.