Millions of pounds of taxpayers' money has been wasted on a screening programme for chlamydia, auditors have said. The first four years of a strategy to cut cases of the sexually-transmitted disease among young people were a waste of time because lessons were not learned on how best to implement the tests, the National Audit Office (NAO) said. Six years after the programme was launched by the Government, only around half of health trusts are testing enough young people to have a significant impact on chlamydia rates, a new study found. Chlamydia is the most common bacterial sexual infection and more than half of all new cases in 2008 were among under-25s. Five years after the Government launched a screening programme, only 4.9 per cent of 15 to 25-year-olds were being tested under the programme despite the target being 15 per cent. A third of the £150 million allocated by the Government for the scheme has also been spent on other things by PCTs meaning only £100 million has gone into it, today's report said. The NAO said the scheme had not proved value for money and predicts £17 million could have been saved in one year if PCTs had managed to keep their costs to an achievable £33 per test. Instead, costs have varied widely - to as much as £255 per test.