Encouraging Compliance with the Modern Slavery Act among AIM Listed Companies

Modern slavery remains a growing yet under‑policed risk for UK companies, and a material concern for ethical investors. Through the Votes Against Slavery (VAS) initiative, a coalition of investors is urging AIM‑listed and FTSE 350 firms to deliver credible and consistent, board‑level accountability on forced labour risks. 

In this article, Castlefield Stewardship Assistant Ffion Spencer outlines our support of the VAS initiative and explores how coordinated investor engagement can drive meaningful change, and what early successes tell us about the power of stewardship in action.

Modern slavery, encompassing practices such as human trafficking, slavery, servitude and forced labour, is a significant global issue, with an estimated 50 million people affected worldwide[1]. In the UK, government statistics show that the number of people affected by modern slavery is rising, with 2025 recording the highest number of referrals to government support on record.[2]

Enforcement of the Modern Slavery Act remains inconsistent, leaving workers exposed to harm and creating material legal, operational and reputational risks for companies and investors. The Votes Against Slavery initiative seeks to strengthen corporate responses by encouraging meaningful compliance with both the Act itself and the intent of the legislation.

The Modern Slavery Act requires companies to publish a clear and robust modern slavery statement explaining how they identify and address forced labour risks within their operations and supply chains.

As part of this Rathbones-led initiative, we signed an investor letter sent to all AIM- listed companies. The letters were backed by 169 investors representing £1.74 trillion in assets under management. As part of the initiative, companies identified as non‑compliant are contacted directly and given the opportunity to improve their disclosures ahead of the AGM season.

Companies that fall within the reporting threshold of the Act must demonstrate that they have met the following minimum legal requirements:

• Director sign‑off: The modern slavery statement must clearly show director sign‑off, including the director’s name, job title and the date of sign‑off.
• Annual updates: Statements should be updated annually, with Home Office guidance recommending publication within six months of the company’s financial year‑end.
• Board approval: The statement must confirm that it has been approved by the board of directors, including the date of approval.
• Website publication: The statement must be published in a prominent location on the company’s UK website homepage.

The letters, which were tailored to set out the specific actions required for each company to achieve compliance, targeted a number of Castlefield investee companies held within the Thoughtful UK Smaller Companies Fund. These included Anpario, Fintel, Judges Scientific, Microlise, Optima Health, Strix, Tracsis, Inspiration Healthcare and Tribal.

While the engagement is ongoing, progress to date has been encouraging. Two companies have already implemented the requested changes, and a further five have committed to making the necessary improvements within clearly defined timelines.

While the engagement is ongoing, progress to date has been encouraging. Two companies have already implemented the requested changes, and a further five have committed to making the necessary improvements within clearly defined timelines. Engagement will continue with the remaining companies ahead of their Annual General Meetings, where investors may choose to vote against certain resolutions if compliance is not achieved.

Outcome: Although the engagement remains ongoing, progress to date has been positive, with a 78% success rate. Two companies have made the required changes, and a further five have committed to time-bound improvements. Continued engagement will focus on supporting these companies, as well as the remaining non‑responders, through to full compliance.

Written by Ffion Spencer 

This article was originally published as part of our Q1 2026 Investment Management Report (IMR).

Information is accurate as at 20.04.2026. Opinions constitute the fund manager’s judgement as of this date and are subject to change without warning. The officers, employees and agents of CIP may have positions in any securities mentioned herein. This material may not be distributed, published or reproduced in whole or in part. With investment, capital is at risk.