Senior HR Business Partner - 15 month FTC in Slough

Middlemore are retained by a prestigious, UK-centric SME seeking an experienced interim HR professional to join on a 15-month fixed-term contract from October 2026. This is a newly scoped role for an HR Business Partner who will also operate as the firm's Employee Relations subject matter expert.

Reporting to the HR Director, the successful individual will partner with their own client group, whilst also serving as the internal expert for employee relations — acting as the point of escalation for complex, sensitive and high-risk casework, whilst also providing pragmatic guidance on the more routine volume of day-to-day ER matters. Beyond the ER remit, the role carries broader HR business partnering responsibility, making this a genuinely rounded, high-impact position.

• Employee Relations Expertise
  • Deep, hands-on experience managing complex ER cases end-to-end — spanning disciplinary and grievance, whistleblowing, protected disclosures, harassment and bullying, performance management and settlement negotiations.
  • Proven ability to assess legal risk, exercise sound judgement under pressure, and manage sensitive matters with absolute discretion.
  • A track record of reducing reliance on external legal counsel through strong in-house ER capability — a genuine cost-saving differentiator.
• UK Employment Law
  • Comprehensive and current knowledge of UK employment legislation, with the ability to navigate an increasingly complex and fast-evolving legal landscape with confidence.
  • Fluency across the key legislative frameworks that govern the modern employment relationship — and the commercial nous to apply them proportionately.
  • The ability to translate complex legal developments into clear, actionable guidance for HR colleagues and line managers, without losing the nuance.
• Transformation & Change-Driven ER
  • Proven experience leading on ER strategy within organisations undergoing transformation — particularly where technology adoption, automation, role redesign and process modernisation have generated workforce anxiety, redundancy risk or changes to terms and conditions.
  • Experience managing the ER implications of restructuring, including collective consultation, at-risk processes and the people communication challenges that accompany structural change.
  • The credibility and composure to advise senior stakeholders when the commercial and people agenda are in tension.
• Commercial & Strategic Acumen
  • Commercially astute, with the ability to frame ER advice in the context of business risk, reputational exposure and cost — not just legal compliance.
  • Experienced in coaching and upskilling HR business partners and line managers, building internal capability and reducing unnecessary escalation.
  • Adept at identifying ER trends, building meaningful MI and presenting insight that enables proactive rather than reactive people management.
• Cultural & Behavioural Fit
  • Comfortable operating in a high-touch, relationship-driven environment where standards are high and discretion is non-negotiable.
  • Able to hold firm on process rigour whilst remaining pragmatic, empathetic and solutions-oriented.
  • A natural collaborator who builds trust quickly across all levels of an organisation.

We are open to two distinct profiles:

• A seasoned HR generalist with deep, demonstrable ER expertise.
• An ER or employment law specialist ready to step into a broader HRBP remit.

Full or part-time working arrangements will be considered for the right individual.

The role offers:

• Basic salary of £100,000–£110,000.
• Circa £15,000 completion bonus.
• Comprehensive benefits package.
• Hybrid working.
• The opportunity to operate as a genuine SME within a sophisticated, high-touch environment at a genuinely interesting moment in its evolution.

Calibre is everything. If you are credible, commercially sharp and thrive in environments where discretion, judgement and technical depth matter in equal measure — this is worth a conversation.