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How Welsh Revenue Authority (WRA) statistics meet the Code of Practice for Statistics and the dimensions of value, trustworthiness and quality.

First published:
15 August 2019
Last updated:
View update history


Value of Landfill Disposals Tax (LDT) statistics

LDT statistics are a valuable source of data on the level of waste going into landfill.

Forecasting LDT revenues for Wales in future is an important use of LDT statistics. The Office for Budget Responsibility produce LDT forecasts to coincide with Welsh Government and UK Government budgets.

Statistics published in other UK countries

HMRC and Revenue Scotland publish statistics for the equivalent taxes in England and Scotland respectively. Up until April 2018, statistics on landfill disposals in Wales were included in the HMRC bulletin, but not shown as separate values within the England and Wales data.

HM Revenue and Customs - Environmental Taxes Bulletin

Revenue Scotland – Scottish Landfill Tax Statistics

In the methods section of the statistical releases, we set out how we adjust the data to reflect the tax due in the quarter. This allows us to estimate and report LDT due in that quarter.

HMRC report on the tax returns submitted in each month, which depend on the accounting periods of the landfill site operators. HMRC then make some accounting adjustments to reflect quarterly activity.

We are unable to publish by month due to:

  • the risk of revealing details of individual landfill site operators
  • and we are keen that the tax reported fully relates to the period against which it is reported

Therefore, please note that data for Wales may not be fully comparable with the data for England published by HMRC, nor with those for Scotland published by Revenue Scotland.


We produce LDT statistics in line with the Code of Practice for Statistics.

As a new producer of official statistics, we are developing our statistical publication processes. We previously published our policy on statistical outputs, including:

  • the professional standards we follow when creating these statistics
  • how the WRA Lead Official for Statistics independently manages the content and timing of outputs
  • how we notify users of upcoming outputs
  • how data is collected, stored and managed
  • and that staff involved in producing statistics will undertake continuous professional development in line with the Civil Service competency framework and the Government Statistical Service (GSS) competency framework


We are still assessing the quality of the data. We will continue to do so as more data are received.

We have assessed the interest and potential quality concerns in-line with the Government Statistical Service guidance on the use of administrative data, identifying any potential quality concerns. The table below presents our current assessment.

Data source

Public interest profile

Level of risk of quality concerns

Level of assurance information to be developed

LDT returns



A1 – basic assurance

When preparing our statistical releases, we work closely with WRA operational staff to identify further issues during collection and processing of individual returns. We developed some quality controls around the tax returns which flag up potential areas of concern to our operational staff. They can then contact landfill site operators to correct potential issues.

These checks have highlighted that there are some very minor rounding issues within the data supplied to us. This is mainly due to multiple site submissions and weighbridge rounding. These issues result in internal consistency differences of less than £10 in aggregate, well within the rounding parameters we have used in presenting the results.

Further examples of quality issues we discovered and actions taken are set out below.

Example 1

By looking at the internal consistency of the data across all returns, we found some issues where our guidance had been ambiguous and where some water discount weight had been recorded against taxable disposals. We revised the guidance to make it clearer and confirmed that all landfill site operators involved had then followed the new guidance, correcting data as necessary ahead of publication.

Example 2

We have introduced a new tax return for landfill site operators to complete, designed in consultation with operators. For disposals at the lower rate of tax, we now collect data by List of Waste (LoW) code, also known as European Waste Catalogue (EWC) code and for fines material, by waste producer. If there are rise or falls in lower rate disposals, we can identify how this change is made up, and if for example the waste has been disposed of elsewhere in Wales. This leads to more operational checks, all of which leads to greater confidence in the data provided by operators to us, and ultimately greater confidence in the statistics we publish.

The new return also allows us a method to either:

  • automatically derive a total tax from the underlying base data
  • where the tax is self-assessed, ensure it lies in an appropriate range based on the more detailed weight figures provided

Methods used to adjust data for different accounting periods

The majority of landfill site operators have standard accounting periods for reporting to the WRA. These align with the end of our reporting quarters. A small number of landfill site operators use different start and end dates for reporting to the WRA. The Methods section in the statistical releases explains how we account for this issue when producing estimates for the current and previous reporting quarters.

Future revisions to data

The data in each release is currently provisional. We may revise the data in future releases to account for updates to returns, for example following routine mitigation and recovery checks carried out by the WRA.

The Methods section in each release covers planned revisions to the data, and the consequent marking of the most recent quarter’s data as provisional. However, the more ad-hoc revisions required following mitigation and recovery checks are less predictable.

For example, there are currently relief claims being assessed and, in these cases, the waste in question has currently been accounted for within the lower rate estimates presented. If the relief is approved the impact may be backdated to cover previous quarters, so that an unplanned revision to the data presented here may arise. Where unplanned revisions are necessary to historic data, we will always make it clear the reasons why in the relevant release.

Coherence with other data

For Environmental Permitting purposes, Natural Resources Wales collect quarterly data on input and output waste at permitted waste sites including disposals at landfill sites. Natural Resources Wales collect this data (using the ‘permitted waste returns’) from site operators, waste collectors and processors, in order to monitor compliance with permit conditions. Our operations staff access and review this data on a quarterly basis, mainly from the perspective of assessing tax risk for LDT. 

The List of Waste (LoW) codes are used in both data sets and we collect them as a means of quality assurance and to assess tax risk. The LoW code is collected for all data in the permitted waste returns, whereas in LDT returns, the LoW code is collected only for certain disposals. The LoW codes are not exclusively standard rated or lower rated and therefore on their own, cannot be used to infer the rate of tax that may apply.

Another difference between the 2 sources is that in the permitted waste returns, data relating to disposals for restoration of a landfill site are submitted under a ‘recovery’ rather than a ‘disposal’ code. For LDT, any disposals for site restoration purposes are treated as a taxable disposal. Landfill site operators may only claim site restoration relief if certain criteria are met.

When comparing the 2 sources, there are several other reasons why data for a particular time period may not align:

  • material deposited by landfill site operators in an approved non-disposal area (such as material stockpiled for future site restoration) is not a taxable activity and data related to this is not included in the LDT return. At the time material leaves the non-disposal area, if it remains on the landfill site, it becomes subject to normal tax rules and is to be included in the LDT return. In the permitted waste returns, there is no such concept of a non-disposal area
  • some landfill site operators have non-standard accounting periods agreed with us for submitting their tax returns. These may not align with the periods in the permitted waste returns. Our glossary page provides more information on non-standard accounting periods
  • landfill site operators submit permitted waste returns to Natural Resources Wales based on periods when waste was received at the site. LDT returns are based on when the tax becomes chargeable. This can be either when a disposal is made or when an invoice is issued, which is often later than the date of the actual disposal. This issue may be more apparent when comparing data for quarterly periods, but less so for longer time periods, such as comparing annual data

Although the data from the permitted waste returns does have some use for quality assuring LDT data, the usefulness of comparing the two different datasets is limited somewhat due to the reasons outlined above.