The number of crimes being solved by police has fallen or ground to a halt in nearly two thirds of forces in England and Wales, The Daily Telegraph has learned.

Experts said the poor record on catching criminals called into question the effectiveness of the extra billions of pounds spent by Labour on policing over the past decade.

The detection rate has fallen by 1.5 percentage points since 1997 to 30.3 per cent of all crimes reported to the police in 2006/7, not including the British Transport Police.

The rate fell or remained the same in 27 forces, increasing in 16. North Wales had the highest clear-up rate - 48 per cent of all record crimes - while Bedfordshire Police had the worst detection rate - just 18 per cent.

Police spending is estimated to have risen from pounds 8 billion in 1998 to pounds 10.1 billion by 2004/5. Over the same period, crimes recorded by police rose from five million to 5.5 million a year.

Last year, every warranted officer detected about 10 crimes per year, the same level as in 2001. For each detection the police spent pounds 10,000 - 10 per cent more in real terms than in 2001.

Richard Garside, the director of the Centre for Crime and Justice Studies at King's College, London, said: "After over a decade of investment and reform, the taxpayer may be left asking what has been achieved.''

The Tories blamed the low rates on officers spending too much time on red tape and "box-ticking''. David Ruffley , the shadow police minister, said: "One hour of every five hours of officers' time is spent on patrol. The Government needs to take action to cut red tape.''

A Home Office spokesman said: "Police forces deserve credit for playing their part in driving down overall crime by a third over the last decade. Whilst the detection rate has held broadly steady during that period the range of powers available to the police to deliver swift, effective justice has broadened.''