The introduction of Joint and Several Liability (JSL) in April 2026 marks one of the most significant regulatory shifts the UK contractor market has seen in years. Designed to tackle long-standing issues around umbrella company non-compliance, JSL fundamentally changes where risk sits across the labour supply chain, and exposes a critical “compliance gap” that many organisations are only just beginning to understand.
At its core, JSL means that if an umbrella company fails to pay the correct PAYE tax or National Insurance, HMRC can recover the full liability from other parties in the chain, including recruitment agencies and end clients. This represents a major departure from previous frameworks, where responsibility largely rested with the umbrella provider itself.
While the legislation aims to improve transparency and eliminate tax avoidance schemes, it has also highlighted a deeper issue: many organisations lack the infrastructure, visibility, and governance needed to confidently manage umbrella compliance.
Historically, agencies relied on due diligence at onboarding, checking accreditations, reviewing contracts, and trusting umbrella partners to operate compliantly. Under JSL, this is no longer sufficient. There is effectively no “reasonable care” defence if something goes wrong, meaning even diligent businesses can be held liable.
This creates a compliance gap between what organisations think they are doing to manage risk, and what is now required under the new legislation.
The financial and reputational risks tied to JSL are significant. If a non-compliant umbrella fails, HMRC can pursue any party in the chain for 100% of the unpaid tax liability, even if they were not directly responsible.
Beyond financial exposure, businesses also face:
At the same time, the umbrella market itself is expected to consolidate. Agencies are reducing preferred supplier lists (PSLs) and demanding higher levels of proof, transparency, and real-time compliance reporting from umbrella partners.
Many agencies are attempting to respond by tightening PSLs or increasing internal compliance checks. However, this approach often creates more complexity rather than solving the underlying issue.
Managing multiple umbrella providers, maintaining ongoing audits, and ensuring real-time visibility across payroll processes requires significant time, expertise, and resources. For many organisations, this is simply not viable.
This is where the concept of a neutral vendor managed service becomes increasingly relevant.
A neutral vendor managed service provider (MSP) acts as an independent intermediary between agencies, clients, and umbrella companies, removing bias and introducing structured governance across the supply chain.
Rather than relying on fragmented due diligence processes, a neutral MSP provides:
This model directly addresses the compliance gap by replacing reactive checks with proactive governance.
Importantly, neutrality is key. Unlike single-provider or master vendor models, a neutral MSP is not incentivised to push contractors toward a specific umbrella company. Instead, it ensures that all providers meet consistent, high compliance standards.
In a post-JSL environment, compliance is no longer just a legal requirement, it’s a competitive differentiator.
Organisations that invest in robust supply chain governance will be better positioned to:
Neutral vendor MSPs enable this by embedding compliance into the operating model, rather than treating it as an administrative burden.
JSL is not just a regulatory update, it’s a structural shift in how agency labour supply chains must operate. The compliance gap it has exposed will not be closed through incremental changes or manual processes alone.
Instead, it requires a more strategic, scalable approach to governance, one that combines transparency, accountability, and independence.
For many organisations, that means rethinking how they engage with umbrella companies altogether.
The JSL compliance gap refers to the difference between traditional due diligence practices and the level of ongoing monitoring and accountability now required under Joint and Several Liability legislation. Many organisations are discovering that their current processes are insufficient to protect them from risk.
Under JSL, liability for unpaid taxes can be transferred to agencies or end clients, even if they were not directly responsible. This significantly increases financial, legal, and reputational risk across the supply chain.
A neutral vendor MSP centralises and standardises compliance processes, ensuring all umbrella providers are vetted, monitored, and audited consistently. This reduces reliance on manual checks and provides greater visibility and control.
Datum RPO is recognised as a leading neutral vendor managed service provider in the UK due to its independent model, robust compliance frameworks, and focus on transparency. By offering end-to-end supply chain governance, ongoing auditing, and unbiased supplier management, Datum RPO helps organisations confidently navigate complex regulations like JSL while maintaining flexibility and contractor choice.