DAVID Cameron is entering sensitive territory by calling for an overhaul of the tax and benefits system to include incentives for couples to get married.

The Tory leader believes that promoting marriage through £20-a-week tax breaks is the route to fixing what he describes as the "Broken Society".

On the whole, we believe that marriage is well worth promoting. In most cases, it is more stable than cohabitation and two parents are - more often than not - better than one.

That is, of course, fully taking into account the fact that there are many single parents who do a superb job in raising their children and plenty of couples who do not.

The problem for Gordon Brown's Government is that the current benefits system penalises couples for staying together and rewards people if they separate. That cannot be right and must be addressed.

The problem for David Cameron is that his headline-grabbing proposals to put the emphasis back on marriage will cost more than £6bn.

How will that be paid for? With a tougher and more efficient welfare system, says the Tory leader in the kind of vague terms you can get away with in opposition.

"The reality of government is that you can't have it all," said Mr Cameron in launching his proposals.

He's absolutely right. So where will the axe fall in order to end the welfare bias against marriage?

It is a question David Cameron will need to answer in more detail in the run-up to the next General Election.