£150 a year tax break if you are married?
Income tax is all about balance. There are countless possible ways of setting thresholds and providing tax breaks, so certain principles must be used. For Liberal Democrats the key principle is one of redressing inequalities.
I'm not so keen on using personal taxation to try to change people's behaviour. Other types of tax, such as the green taxes we support, can be used to encourage people to change their ways. But Income tax should be about a fair distribution of wealth, leaving people themselves to decide how they want to spend their money.
The Conservative commitment to provide a tax break of £150 a year to every married couple (civil partnerships included) falls into the 'let's change people's behaviour' category.
Not only is it doomed to failure, but it will have a unpleasant side effects.
Do you really believe that a couple will decide to get married, rather than live together, simply in order to get an extra £150 per year? How many years will it take to cover the cost of even a modest wedding?
The argument the Tories give is that a couple with young children are more likely to stay together if they are married than if they are not. That may be true, but I'm not sure that the act of marriage itself is the determining factor - surely the strength of the relationship is the key? Presumably people who get married have committed themselves to a strong relationship, and that is why they are more likely to stay together. Any attempt to entice people into marriage when the relationship is not strong enough will be bound to fail.
This tax break is clearly a bribe to 'ordinary hardworking families' who always take centre stage at election time.
But it is bad.
I can remember the days when marriage was enshrined in the income tax system. There was a far more substantial marriage allowance than the one proposed by the Tories now. But it was dependent on a personal taxation system that taxed couples jointly.
To make this work, the woman was required to divulge all her income to her husband - yes, that way round only. Their incomes were added together and the marriage allowance applied to the total.
Thank goodness we have got beyond that system and now have individual taxation. Women and men can arrange their finances, shared or individually, as they see fit. Either person in a marriage can have their own private savings without being forced to tell the other. Not only is this right for all individuals, but it is particularly important for people who are trying to escape a violent partner.
And yet something like this will be required to make the Tory marriage tax break work. The couple will be forced to tell each other what their income is, so that they can decide which one of them should transfer £750 of their personal allowance to the other.
Then there are the anomalies that make this such an unfair idea. Someone who has just been widowed, or whose partner leaves them, will lose their tax break, even though they may be left as a single parent with higher expenses.
Liberal Democrats are proposing a much simpler approach to taxation. Raise the personal tax threshold so that no-one earning less than £10,000 a year will pay any income tax at all. That's a fair tax break, and one that truly benefits the people on the lowest incomes.