Index of Production, UK: September 2025

• Production output was estimated to have decreased 0.5% during Quarter 3 (July to Sept) 2025, compared with Quarter 2 (Apr to June) 2025.

• The largest negative contributor to the quarterly fall in Quarter 3 2025 came from "manufacturing" (down 0.8%), supported by "mining and quarrying" (down 1.5%); this was partially offset by increases in "electricity and gas" (up 0.7%) and "water supply and sewerage" (up 0.6%).

• 6 of the 13 subsectors in "manufacturing" decreased during Quarter 3 2025; the largest negative contributions came from "transport equipment" (down 4.5%), "basic pharmaceutical products" (down 4.3%) and "chemical products" (down 5.6%).

• Monthly production output was estimated to have decreased 2.0% in September 2025; this follows a rise in August 2025 (up 0.3%) and a fall in July 2025 (down 0.1%).

• The fall in monthly production output in September 2025 resulted from widespread weakness across the four main sectors, with decreases in "manufacturing" (down 1.7%), "electricity and gas" (down 3.4%), "mining and quarrying" (down 3.4%), and "water supply and sewerage" (down 0.7%).

• 7 of the 13 manufacturing subsectors saw a monthly decrease in September 2025, with the largest negative contribution at industry level coming from "manufacture of motor vehicles, trailers and semi-trailers" (down 28.6%); this contributed negative 1.29 percentage points to the overall monthly fall in September 2025; for further information please see Section 3: The production sector of our GDP monthly estimate, UK: September 2025 bulletin.

All data related to the Index of Production (IoP) are available on our Related data page.

The Index of Production (IoP) uses data from a variety of sources. It is calculated by taking turnover and removing the effect of price changes, or by using direct volume estimates.

Most of these data are collected as "turnover values" through the Monthly Business Survey (MBS). Direct volume series are also collected by the Department for Energy Security and Net Zero (DESNZ), and the International Steel Statistics Bureau (ISSB) for steel industries.

The MBS is fully online. Business owners can log on from any location and submit their data at an appropriate time.

From January 2018, Value Added Tax (VAT) data have also been included for 64 production industries for small- and medium-sized businesses. More information is available in our VAT turnover data in National Accounts: background and methodology.

A comprehensive list of the IoP source data can be found in our Gross domestic product (GDP) data sources catalogue.

Response rates for September 2025

MBS response rates were 73.3% for September 2025, based on forms returned. This accounted for 82.1% of total turnover coverage of the sample population. For further information, see our Current and historical MBS (production) response rates dataset.

Quality and methodology

The data reported in IoP bulletins and datasets are estimates that are subject to uncertainty, such as sampling variability and non-sampling error. More information is available in Section 2 of our Uncertainty and how we measure it for our surveys web page.

More quality and methodology information (QMI) on strengths, limitations, appropriate uses, and how the data were created is available in our Index of Production, UK QMI.

Accredited official statistics

These accredited official statistics were independently reviewed by the Office for Statistics Regulation in April 2014. They comply with the standards of trustworthiness, quality and value in the Code of Practice for Statistics and should be labelled "accredited official statistics".

Revisions to Index of Production

In line with the National Accounts Revision Policy this release is open for revision for July and August 2025. 

Table 1 shows the revisions to Index of Production (IoP) and its main sectors from July 2025 to August 2025 since the last publication on 16 October 2025.

The upward revision to July 2025 in "Section D – Electricity and Gas" is because we have incorporated the latest DESNZ source data consistent with their Energy Trends release.

Restarting of Producer Prices publications

Following the restart of monthly business prices publications on 22 October 2025, business prices data with corrected chain linking methods and updated historic weights have been used in the IoP dataset for producer price indices (PPI), import prices indices (IPI), export price indices (EPI), and service producer price indices (SPPI) for July, August and September 2025 in this release. The quarterly SPPI estimates are splined to months for use in IoP calculations.

These updates to business prices data will be incorporated in IoP in line with our national accounts revisions policy.

Further information on the chain linking error and the impact of methodological changes in the producer prices dataset are detailed in our Impact of correction to chain-linking methodology used in Producer Price Indices and Services Producer Price Indices: October 2025 article, published on 22 October 2025.

Seasonal adjustment

The monthly estimates of IoP are seasonally adjusted. Seasonal adjustment is the process of removing the variations associated with the time of year, or the arrangement of the calendar, from a data time series.

IoP estimates, as for many data time series, are difficult to analyse using raw data because seasonal effects dominate short-term movements. Identifying and removing the seasonal component leaves the trend and irregular components.

We use the X-13-ARIMA-SEATS approach to seasonal adjustment. Seasonal adjustment parameters are monitored closely and are regularly reviewed. For more information, please see our Seasonal adjustment methodology page.

In our IoP estimates, seasonal adjustment is applied at the industry level. The seasonally adjusted series are aggregated to create estimates by sector and total IoP output. As part of our quality assurance approach, residual seasonality checks are regularly completed by our time series analysis team on both the directly seasonally adjusted series and the indirectly derived aggregate time series.

This topic is explored further in our Assessing residual seasonality in published outputs article, updated on 30 September 2025.