## Facts

- The claimants challenged the legality of rules under the Jobseekers (Back to Work Schemes) Act 2013 requiring participation in unpaid work programmes.
- The disputed rules operated retrospectively, affecting periods before the Act commenced.
- Claimants argued these retrospective rules harmed their rights and contravened principles of legal certainty.
- The case focused on whether the Secretary of State had authority to impose rules altering conditions for jobseeker's allowance with retrospective effect.

## Issues

1. Whether the Secretary of State had legal authority to implement rules with retrospective effect altering benefit entitlements.
2. Whether the application of retrospective welfare rules violated claimants' rights or the principle of legal certainty.
3. To what extent the concept of reasonable expectations limited the ability to change benefit conditions retroactively.

## Decision

- The Supreme Court held that the retrospective rules were ultra vires and exceeded the Secretary of State’s lawful authority.
- The Court emphasised the requirement for clear legal standards, holding that retroactive changes to benefit rules are unfair unless plainly permitted by Parliament.
- The ruling acknowledged that individuals should be able to rely on existing social security rules to organise their affairs.

## Legal Principles

- Laws must be clear, consistent, and accessible, enabling individuals to know their entitlements and obligations.
- Parliamentary intention for retrospective legal changes must be explicit; Henry VIII clauses should not be read as granting open-ended authority to ministers for retrospective laws.
- The principle of reasonable expectations can be relevant when assessing the lawfulness of retrospective legislation, though its precise role remains unresolved.
- Safeguarding the legal integrity of the social security system requires protecting individuals against sudden or unpredictable changes imposed without clear statutory authorisation.

## Conclusion

The Supreme Court’s decision in R (Reilly) v Secretary of State for Work and Pensions established firm limits on retrospective legislation in welfare law, affirming that only clear Parliamentary intent can justify such measures and reinforcing protections for claimants’ legal certainty and rights.

R (Reilly) v Secretary of State for Work and Pensions [2014] AC 453