By contrast, the Labour leader's had increased by 12.
Overall Mr Miliband's party was on 41%, with the Tories on 32% and Liberal Democrats 11%.Some 26% of those surveyed agreed that Mr Cameron was turning out to be good premier, down three points from April 22.But 54% said the opposite - giving him a net rating of minus 28.
Mr Miliband's score improved to minus 19, as his approval rose eight points to 26% while 45% thought he was doing a bad job.The Tories and Labour were deadlocked on who was most trusted to run the economy, both receiving a rating of minus 29.
Miliband: Labour will work 'for the whole country'
Labour leader Ed Miliband has said his party will work for the whole of the country not just 'the wealthy few,' in an attack on the Conservative's at the launch of his local government strategy ahead of the local elections on 3rd May.
Miliband: Local government strategy will tackle living standards
Ed Miliband has begun to outline his local government strategy in Birmingham. The Labour leader said ; "Labour is changing so that we can change the country. On living standards, on jobs, on the NHS and on crime." On living standards he said;
Every pensioner over the age of 75 won't have to shop around for energy - we will force the energy companies to give you the lowest tariff.
We would cap rail fares on all routes.
We wouldn't be cutting the 50p tax rate for millionaires we'd actually be spending the money to make sure those pensioners tax allowances were put back in place.
Ed Miliband is expected to announce a Labour pledge to make tackling vandalism and anti-social behaviour a priority. He will also highlight efforts by Labour councils to set up work programmes and promise to protect 6,000 nurses from Government cuts.