You asked:

What were the average number of crimes committed and their financial cost in Britain, please expressed as a time series?

We said:

Thank you for your enquiry on the average number of crimes and their financial cost in Britain. Unfortunately, we do not hold the data you require. We collect and publish crime data for England and Wales only, from both the Crime Survey for England and Wales (CSEW) and police recorded crime data sent to us by the Home Office. We do not hold any data on crime for Britain as a whole.

In addition, neither of these sources covers all crime. The CSEW provides estimates for a selected range of crimes experienced by the general public, including those not reported to the police, while the police recorded crime data covers crimes classified as notifiable offences by the Home Office. We do produce a time-series of estimates of crime, using both CSEW and police recorded crime data, which is published alongside each of our quarterly bulletins, the latest version of which was ‘Crime in England and Wales, year ending June 2017’ and can be found at the link below.

https://www.ons.gov.uk/peoplepopulationandcommunity/crimeandjustice/bulletins/crimeinenglandandwales/june2017

Figure 1 from this bulletin shows total crime estimates from the CSEW and from police recorded crime data, for selected years from the year ending December 1981 to the year ending June 2017. The data behind this chart is also available, and can be found here:

https://www.ons.gov.uk/peoplepopulationandcommunity/crimeandjustice/datasets/crimeinenglandandwalesbulletintables

We do not hold any data on the cost of crime. There was an analysis carried out by the Home Office in 2005, looking at the economic and social costs of crime, which may be of some use to you. The publication is entitled 'The economic and social costs of crime against individuals and households 2003/04' and can be found at the link below.

http://webarchive.nationalarchives.gov.uk/20100408123402/http://www.crimereduction.homeoffice.gov.uk/statistics/statistics39.htm

If you have any further questions around this analysis, I would suggest contacting the Home Office directly. They can be reached at CrimeandPoliceStats@homeoffice.gsi.gov.uk.

Hopefully this is helpful to you. If you would like any further information, you can simply email us at CrimeStatistics@ons.gov.uk and we will endeavour to help. If you have any further questions, please do not hesitate to ask.