Politics 2 July 2013 The message of the marriage tax: two people good, one person bad A very odd tax break. Sign UpGet the New Statesman's Morning Call email. Sign-up David Cameron believes in marriage. So do I, it would be such a weird thing to make up - so I'm not really sure why it needs a tax break to make it flesh. The idea of a tax break for married couples has had an on-off relationship with the Conservative party over the years. Right now, Tim Lougton, a rebel Tory MP, has pressured David Cameron into bringing forward proposals to give married people £150 in tax breaks - the "start of something bigger", says Lougton. "It’s an important message and it’s also the start of something. £150 is a figure that was plucked out of the air as how it might start; the amendment I’ve been putting forward gives the Chancellor maximum flexibility as to how generous he can be," he told the Today programme. But Nick Clegg slammed the policy - and I have to say I agree with him. Here's the first thing, whether the start of something bigger or not, £150 really is not very much. Not enough to maintain a loveless marriage over. Probably not even enough to stimulate passionate love where there was none. (My research tells me it took £10,000 a year for Elizabeth Bennet, and that's before inflation). No, the point is, as Cameron said later, it's symbolic. It's an "important message" from the Conservative party, and that message is: two people good, one person bad. But we know this already. Everyone knows this. Even films know this - it's the key indicator of whether you're watching something arty and highbrow (sad lonely person at end) or something by Richard Curtis (Hugh Grant gets married). This is why people stay in relationships when they're not really sure they're enjoying it any more, or when they're suffering from domestic violence (2 women a week are killed this way). It's like the Conservative party have become advocates for a 365 day Valentine's day. Which is great, if you're married, but then it's already great if you're married. Here's the wider point: we don't need to provide extra motivation for things we are already motivated to do. Policy doesn't always have to be about psychology. Sometimes it should be about support. The Right often argue that their values are far more in line with our instincts. They're correct - and that's exactly why we need the Left. › Never mind a pay rise, let’s stop paying our MPs to fail David Cameron approves this cake. Photograph: Getty Images Martha Gill writes the weekly Irrational Animals column. You can follow her on Twitter here: @Martha_Gill. Subscribe For more great writing from our award-winning journalists subscribe for just £1 per month!