This metric presents the first full year of data collection, covering 1 April 2025 to 31 March 2026. It is an actions‑based metric, drawing on data collated primarily by the UK Centre for Ecology & Hydrology (UKCEH), working with partners including the GB Non‑Native Species Secretariat (GBNNSS). It uses evidence from sources such as iRecord, NNSS alert emails and direct reports, and operational datasets including the UK Species Inventory (UKSI) to estimate the number of species prevented from establishing.

The methodology combines activity across the invasion pathway, particularly contingency responses and eradication, and applies rules and assumptions to estimate prevention events. As a new metric, these data provide an initial baseline only. Data collection will continue to build a consistent time series through to 2030/31, and the methodology may be refined as evidence, data availability and approaches develop. Further details are set out in the interim Prevention of INNS Establishment (Actions‑based metric) methodology document.

Indicative data (see table below) show that 128 target‑relevant reports were recorded in England in 2025/26. Of these, around 50% (60 reports) were confirmed, involving 53 species. All confirmed reports were reviewed by relevant government bodies for appropriate action. This activity contributed to preventing the establishment of three species.

This actions‑based metric provides a structured but simplified estimate of prevention activity and is subject to uncertainty. It draws on multiple datasets, including iRecord, NNSS reports, and UKSI, alongside data collated by UKCEH and partners, and relies on assumptions about whether species would have established in the absence of intervention. Actions are aggregated into prevention events using defined rules, which may vary by species and context.

Data gaps and inconsistencies in reporting, detection and coverage may lead to underestimation or imbalance across action types, and there remains a risk of double counting or misclassification despite validation. The metric should therefore be interpreted as an indicative measure of prevention effort and contribution rather than a definitive count of species prevented from establishing. Work is ongoing with partners to improve data collection and consistency, increase reporting and awareness, strengthen quality assurance, and refine the analysis and methodology.