The Metropolitan Police have announced new guidelines designed to ‘screen out’ thousands of crimes without investigation.

The cost-cutting move allows London’s police officers to assess whether it is practical and proportionate to launch an inquiry.

Judging by the news reports, this may have seemed like a completely new idea. But data obtained by FactCheck shows that the Met already screens out hundreds of thousands of crimes each year.

The new guidelines merely expand the current policy.

FactCheck’s figures reveal that almost a third of crimes reported between 2014-2016 were dropped without any further investigation.

The figures – which were released to FactCheck under the Freedom of Information Act – show that vehicle crimes were the most likely to be screened out last year.

Only a third of vehicle-related offences in London led to a full investigation. And half of all burglaries were also screened out.

Other types of crime are far more likely to be investigated: weapons, drugs and sexual offences have investigation rates of nearly 100 per cent.

But, despite this, police are still twice as likely to screen out sexual offences than they are to screen out drug cases.

Here’s the breakdown for the main crime categories.

The investigation rate is even higher when we look at specific offences, within these broad categories.

Last year, the Met failed to fully investigate more than 70 per cent of thefts from vehicles in London. And around half of bike all thefts were also not followed up.

This graph shows the ten offences with the highest ‘screen out’ rate in 2016.

However, the proportion of cases being dropped has actually come down over the last three years.

In particular, police are screening out a far smaller proportion of car and bike thefts than they used to (although a very high proportion of cases are still screened out).

In 2014, some 68 per cent of bike theft reports were dropped, compared to around 50 per cent in 2016.

Overall, the ‘screen out’ rate dropped by nearly six per cent between 2014 and 2016.

However, for certain crimes, the police are becoming less likely to investigate.

These include forging drug prescriptions (up eight per cent) and forging driving record (5.4 per cent).

The rate for robbery, sexual offences and violent disorder has also gone up slightly.

What does ‘screening out’ really mean?

When a crime report is ‘screened out’, that doesn’t mean there is literally no investigation at all.

In many cases, officers will carry out an initial routine exercise to find out basic information. This might include things like establishing what type of crime is being reported, whether there are any victims, and whether they think CCTV might be able to identify the criminal.

They then make a decision on whether it’s worth launching a full investigation.

The Met told FactCheck that some crimes – such as murder, kidnap and rape – will always be investigated, no matter what.

So, what’s changing?

The changes simply allow low-level cases to be screened out more quickly, when the conclusion is clear from the outset.

Police have refused to publish the guidelines, saying it was an internal document, so FactCheck cannot independently verify exact the details.

However, the Met’s Deputy Assistant Commissioner, Mark Simmons, has said it will allow officers to make “judgements about whether it would be proportionate to continue further with an investigation in some lower level crime”.

“With the pressure on our resources it is not practical for our officers to spend a considerable amount of time looking into something where for example, the value of damage or the item stolen is under £50, or the victim is not willing to support a prosecution.”