Founding Head of Public Sector

Job title: Founding Head of Public Sector

Location: London; 4 days in-office, 1 day wfh

Reports to: Chief Commercial Officer

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Cosine at a glance

Cosine is the UK's frontier AI lab for autonomous software engineering — not another coding assistant, but our own models, agent stack, eval harnesses, and product layer. We build our agent tooling entirely in-house and post-train open-source models to deliver reliable, enterprise-grade coding performance in security-critical settings.

Our offerings can be used as SaaS, deployed on VPC, on-prem or fully air-gapped. Through this flexability, we are able to service large-scale, highly regulated enterprises and industries including defence, financial service and healthcare.

We’re backed by YC and were recently selected for the UK’s sovereign AI programme. The company is at a rare stage: deep technical work, real enterprise pull, and a chance to shape how AI is deployed inside defence, banking, government, and other high-trust environments.

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Mission

Own Cosine’s public sector engagement and GTM motion from founder-led relationship building into a repeatable commercial engine.

The role exists to build on Cosine’s growing reputation across government, defence-adjacent bodies, public sector technology teams, and the wider UK sovereign AI ecosystem, turning senior interest into deep institutional relationships, clearly understood priorities, and qualified commercial opportunities.

This is a critical sector-building role: part enterprise sales, part partnerships, part market development, part public sector navigation, and part GTM leadership.

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Core responsibilities

1. Lead engagement with public sector organisations and priority accounts

Own Cosine’s day-to-day engagement with priority public sector organisations, including central government departments, arm’s-length bodies, regulators, public agencies, national infrastructure bodies, and public sector technology teams.

Build on Cosine’s growing reputation in sovereign AI, secure deployment, and trusted AI engineering to create senior routes into the right organisations.

Maintain a clear account map across key public sector organisations, including executive sponsors, digital and technology leaders, commercial/procurement stakeholders, policy teams, risk/security owners, and delivery teams.

Move relationships from broad sovereign AI interest into specific, practical areas where Cosine can create value.

2. Build multi-threaded senior relationships

Develop relationships across multiple departments, divisions, seniority levels, and decision-making layers in each target account.

Engage CIO, CTO, CISO, CDIO, digital, data, engineering, architecture, commercial, procurement, transformation, policy, security, and operational stakeholders.

Identify how priorities differ across teams, for example secure AI deployment, software assurance, legacy modernisation, operational resilience, cost reduction, productivity, national capability, procurement risk, and governance.

Build enough trust that Cosine becomes part of the strategic conversation around sovereign AI adoption, not just another vendor responding to tenders.

3. Build Cosine’s understanding of public sector sovereign AI priorities

Run structured discovery across public sector organisations to understand what they truly care about in sovereign AI.

Capture use cases, constraints, buying triggers, objections, governance requirements, security expectations, procurement routes, deployment models, and success metrics.

Translate public sector customer signal into internal intelligence for sales, partnerships, product, research, engineering, marketing, and leadership.

Build a sector view of where Cosine has the strongest right to win, including priority use cases, highest-intent accounts, likely buyer personas, procurement routes, SI influence, and repeatable commercial narratives.

Priority areas to explore include:

Secure AI coding and software engineering inside sensitive or regulated public sector environments.

AI adoption where source code, credentials, data, or infrastructure cannot leave the customer’s control boundary.

Legacy system modernisation and maintenance.

Software assurance, auditability, testing, review, and governance.

Productivity and resilience across public sector digital delivery teams.

Deployment models across public cloud, customer VPC, on-prem, secure environments, and air-gapped environments where required.

National capability, sovereign AI, and reducing dependency on foreign-controlled AI infrastructure.

4. Build towards commercial opportunities

Convert reputation, relationship-building, and market education into qualified pipeline opportunities.

Identify where there is a real public sector problem, accountable owner, budget route, technical champion, procurement path, and reason to act now.

Shape opportunities into concrete next steps: workshops, technical deep-dives, discovery sessions, pilots, proof-of-concepts, deployment planning, bid participation, or commercial proposals.

Work with the wider GTM team to move qualified public sector opportunities through the sales cycle.

Keep a clear view of account status, stakeholder map, open actions, risks, next steps, procurement routes, SI involvement, and commercial likelihood.

The role should focus deeply on commercial pull: serious conversations, mapped accounts, live opportunities, pilots, bid routes, and ultimately revenue.

5. Work closely with systems integrators and delivery partners

Work alongside Cosine’s Head of Partnerships to build and manage relationships with the systems integrators, consultancies, and delivery partners that shape public sector buying.

Identify where SIs can create routes into accounts, provide bid access, support delivery credibility, or help Cosine become part of larger transformation programmes.

Build joint account plans with priority partners where there is a clear public sector opportunity.

Support bid strategy, partner positioning, framework access, and teaming discussions where Cosine is best placed as a specialist sovereign AI or secure AI engineering partner.

Ensure SI engagement is commercially purposeful, with clear ownership, target accounts, bid opportunities, and follow-up actions.

6. Navigate public sector routes to market

Build a clear view of the procurement and commercial routes that matter for Cosine in public sector.

Understand where Cosine should pursue direct engagement, partner-led opportunities, framework routes, innovation pathways, pilots, or inclusion in larger SI-led bids.

Help shape compliant engagement approaches that create trust without relying on frequent hosted events or activity that could create procurement issues.

Use targeted briefings, structured discovery, partner conversations, written materials, and appropriate market engagement routes to progress opportunities.

Work with legal, commercial, partnerships, and leadership to ensure public sector engagement is commercially useful and procurement-aware.

7. Help build the GTM team in public sector

Help define what the public sector GTM motion should become as Cosine scales.

Build the early playbook for account selection, stakeholder mapping, discovery, qualification, partner-led entry, SI engagement, bid strategy, pilot design, procurement navigation, and commercial progression.

Help recruit, onboard, and develop future GTM hires focused on public sector.

Establish the operating cadence for the sector: account reviews, pipeline tracking, partner follow-up, bid tracking, customer insight capture, and internal reporting.

Work closely with SDRs, partnerships, marketing, founders, ente