The nudge, nudge unit has ways to make you pay Sir Jeremy Heywood, the Cabinet Secretary, and his predecessor, Lord O'Donnell, are giving them enthusiastic support. The latter, who chairs the unit's advisory group, says such techniques will bring "revolution not evolution" in Whitehall. He points out that even a 1 per cent increase in people's level of honesty when paying tax or claiming benefits could bring in an extra £7 billion. As a result, all senior civil servants are soon to be taught how to nudge the public into doing what the state wants. Some of the work done by the nudge unit seems impressive enough. For example, there is currently some £500 million in unpaid fines in this country. Trials show that if letters are sent demanding that people pay up, only 5 per cent do so. If text messages are sent, 20 per cent pay. If a text is sent to you by name, warning that the bailiffs are coming, it rises to a third. These strategies were tried out in the South East, and will now go countrywide, bringing substantial savings in the cost of bailiffs (who tend to take people's TVs and furniture and sell them for next to nothing, so there are gains all round). Or take the non-payment of car tax. Initial letters bring in an 11 per cent response - but if people are sent pictures of their cars minus the tax discs, repayment goes up threefold. This autumn, one of the biggest "nudges" will be applied to company pensions, when people will start having to opt out instead of opting in. This auto-enrolment is expected to lead up to 10 million people to start saving for their retirement for the first time, which will ultimately bring dramatic savings in the cost of state support for poor pensioners. The figures showing the impact of such small changes come from what are known as randomised controlled tests - you send different letters to two groups of debtors or drivers, and compare the responses. Grant Shapps, the housing minister, points out that businesses have deployed such random testing for years. He is planning to use the same techniques for a new right-to-buy scheme, enabling as many as 2.5 million people to buy their council houses at a discount of up to £75,000. The key, as he explains, is to use "personalisation" and "social norms." "Instead of writing to 'the householder,"" he says, "you write to them by name, saying that they might be interested to know that many people in their street, with families like theirs, have taken the decision to buy their council houses with a discount. If they respond, we're planning to send them amusing 90-second videos which will make them laugh and which they'll post on Facebook, where they can see what other people are doing. There is something of the young Tony Blair about Mr Shapps: he seems the master of the hard/soft sell and his enthusiasm is disarming. But is randomised testing really the "no-brainer" that he claims? Sending out differently worded text messages doesn't harm anyone, but there are real difficulties in applying such techniques to big-ticket items such as benefits. New medicines are trialled in this way, but only with a huge raft of ethical safeguards - including giving full information to everyone who takes part, obtaining their consent and deciding in advance when the trial should be halted, for example if people are being harmed. Similar safeguards should surely be applied if new benefit systems are being tested. Even the proponents of nudge theory admit that there is still stiff resistance in Whitehall. Some see it as a David Cameron vanity project - the PM has been keen on the idea since his days in Opposition. Some see proposals such as a £100,000 prize draw for all who pay their taxes on time - an idea currently shelved - as inappropriate, because people should pay up anyway. There are also fears that the public will soon come to recognise how they are being manipulated, and will resent it. And while nudge may be winning adherents, some officials insist that the public often need a legislative shove as well.