Sexual assaults and arson are among the crimes that are being ‘screened out’ within a day of being reported

The Metropolitan police are increasingly dropping investigations into serious crimes such as sexual offences, violent attacks and arson within hours of them being reported, the Guardian can reveal.

The UK’s largest force “screened out” 34,164 crimes without further investigation on the day they were reported in 2017, compared to 13,019 the year before. In the first five months of 2018, 18,093 crimes were closed in 24 hours, putting the number for the year on track to exceed last year’s total.

The figures, obtained under freedom of information rules, included a growing number of sexual offence cases that were closed in a day, rising from 20 in 2016 to 49 in 2017 and 32 in the first five months of 2018.

Critics said that the disclosures demonstrated the effect that austerity was having on the force’s ability to carry out its duties.

Screening out is the process whereby the Met decides which offences to stop investigating after a primary assessment. In October 2017, in a move denounced as a “green light to thieve”, the Met said it would screen out more investigations, saying that it would end investigations into many reports of crimes, including burglaries, thefts and assaults, where there was judged to be little prospect of identifying a suspect. The force said the step was necessary to balance the books.

Discussing the policy at the time, deputy assistant commissioner Mark Simmons said: “We are not talking about things like homicide, kidnap, sexual offences, hate crime or domestic violence, but the lower level, higher volume offences.” He gave the example of damage or theft at a value of less than £50.

Data obtained by the Guardian showed that 303 cases of violence with injury have already been screened out in 2018 so far, compared to 290 cases in the whole of 2016. In 2017, 4,670 cases of arson and criminal damage were dropped on the same day they were reported, compared to 2,284 the year before.

In response to the new figures, the Met said that the policy was necessary to ensure the best use of resources and pointed out that investigations were sometimes reopened. But the release prompted an outcry from victims’ charities, campaigners and MPs.

Diana Fawcett, chief officer at independent charity Victim Support, said that 50 sexual offences being screened out on the same day they were reported was “very concerning”.

“We know that victims of sexual assault already face barriers to reporting to the police and this news is likely to undermine public confidence in the criminal justice system and could deter victims from reporting crimes in the future,” she said.

She added that the police should help victims to understand why a crime is not being investigated further by clearly explaining the reasons for this decision, signposting them to independent support to help them deal with the impact.

Diane Abbott, Labour's shadow home secretary, called the findings “deeply troubling”.

“If the Met police are ‘cherry-picking’ cases, victims of serious crimes will not be getting the justice they deserve,” she said.

Abbott argued that funding cuts made by the Conservative government are having a huge impact on the police’s ability to carry out their work.

Last year, mayor of London Sadiq Khan closed 38 police station front counters to save £8m per year, and warned Scotland Yard was "running out of options" regarding resources.

Chris Hobbs, a retired police officer who spent 32 years in the Met, including special branch, said that increased demand on the police, cuts to budgets and struggles to recruit in the criminal investigation department meant that things were “falling through the cracks”.

“It’s not just sexual offences, but all offences – what used to be regarded as a serious offences, burglaryfor example – they have now slipped right down the ladder [in terms of importance]. All sexual offences are heinous crimes but a detective who has a considerable caseload will have to prioritise what they are dealing with in terms of solvability and the seriousness of a crime.”

The Met provided data on the number of crimes that were closed on the same day they were reported from 2013 to 2018. Crimes reclassified as no crimes and resolved cases were removed from the figures.

Previous reporting has shown that the Met screened out around a third of the 2,203,027 crimes reported between 2014-2016.

The Metropolitan police said that all crimes are subject to an initial investigation to identify those that are more likely to be solvable. “The Met deal with nearly 800,000 allegations of crime every year. Investigations must be proportionate and timely – to utilise the best possible evidential opportunities.”

They added: “As soon as a proportionate investigation has been completed and reasonable lines of enquiry have been pursued and exhausted, an investigation will generally be completed. However, this does not necessarily mean an investigation is over. For example, forensic evidence is an important line of enquiry that may result in investigations being re-opened.”

It continued: “Under Home Office counting rules, the category of sexual offences includes a range of offences including exposure and sexual touching.

“In a number of these cases, the victim did not want to proceed with an allegation, but simply wished to alert police to the issue. This can lead to a wider intelligence picture which may result in operational activity in the future.”