Police are failing to record a staggering one in five crimes, including victims' reports of sexual offences and violence.

Almost a million 999 calls are ignored every year due to an obsession with hitting targets.

The scale of the problem is revealed today by Her Majesty's Inspectorate of Constabulary, which describes it as 'inexcusably poor and indefensible'.

More than 800,000 crimes reported to police go unrecorded every year, according to Her Majesty's Inspectorate of Constabulary

The watchdog discovered that 19 per cent of reported crimes are dismissed by forces across the country, with hundreds of rapes and violent offences wrongly recorded as 'no crimes' or removed from force statistics 'for no good reason'. Inspectors found:

More than 800,000 crimes reported to police go unrecorded every year;

A quarter of sexual offences are not recorded, with more than 200 rapes dismissed as 'no crime';

A third of violent crime is not logged, with some 250 offences ignored;

One in five offenders who escape with a caution, warning or penalty notice should have faced a more severe punishment or been sent to court to face jail.

The report says victims are being 'discredited' by police due to a 'target mentality on the front line'. This is resulting in serious crimes being missed, even when they are reported.

In the worst forces, more than a third of reported offences were disregarded.

Yesterday, Her Majesty's Chief Inspector of Constabulary Tom Winsor said hundreds of thousands of victims were being denied justice.

'The first duty of the police is to protect the public and reduce crime,' he said. 'A national crime-recording rate of 81 per cent is inexcusably poor.

'This is not about numbers and dry statistics; it's about victims and the protection of the public.'

The damning report released today reveals officers are routinely failing victims of rape and sexual offences. Almost half of the 43 forces in England and Wales made errors in their recording of rapes, with more than 200 offences written off as no crime having taken place. But inspectors found that in 20 per cent of those cases, the decision was wrong.

A third of violent crime is not logged, with some 250 offences ignored, according to the watchdog

In one instance, a man who raped a drunken woman after leading her into a wood on the pretext of taking her on a walk to sober her up escaped justice simply because the victim had taken some of her clothes off beforehand.

Mr Winsor said police appeared to have a 'principle of presumed consent' to rape. He added: 'The police should immediately institutionalise the presumption that the victim is to be believed.'

Last year, police recorded 3.7million offences. HMIC reviewed 10,267 reports of crime, listening back to 999 calls before looking at the way the incident was handled and recorded. It found that even when crimes were correctly recorded, many were later removed from the system as 'no crimes'. One in five of the 3,246 decisions to cancel a crime record was incorrect.

And a third of victims were not told their case had been dropped.

The audit also looked at punishments, concluding one in five offenders who received a caution, warning or fixed penalty notice should have been taken to court or faced a stiffer penalty. In one force, an assistant chief constable sent an email to staff complaining that levels of serious acquisitive crime were too high and demanding that officers should investigate first and record later.

'It resulted in victims not being believed when they reported crimes and even discredited,' inspectors found. They also found evidence of supervisors interfering to cut the level of crime recorded by 'discrediting' the victim.

A national survey of 17,000 officers found a fifth had felt under pressure not to record a crime in the last six months.

HMIC concluded: 'A number of forces accepted that undue performance pressure had adversely affected crime recording in the past and the culture of chasing targets as ends in themselves had distorted crime recording decisions.'

The worst forces were Hampshire, Merseyside, Avon and Somerset, West Yorkshire, Dyfed-Powys and Greater Manchester.

In one case, the robbery of a young woman who was punched and kicked by an attacker who stole her trainers was reclassified as assault after an officer decided her shoes must have fallen off.

Officers also failed to protect a boy who told his teacher he had been hit by his father at home.

Despite previous reports of the man beating his children, police dropped the case because the family had moved house.

Adam Pemberton, assistant chief executive of Victim Support, said: 'The sheer number of crimes that have been dismissed by the police is alarming. It's equally astonishing that so many victims are not told if the police decide later that no crime took place.