Full-Time

Principal Project Manager

Updated on 8/11/2026

ASSYSTEM

ASSYSTEM

5,001-10,000 employees

Engineering services for design, construction, commissioning

No salary listed

Bristol, UK

Hybrid

Three office days per week may be required in Bristol, Glasgow, or Newcastle, with travel to customer sites as needed.

UK Top Secret Clearance Required

Category
Business & Strategy (1)
Required Skills
Microsoft Office
ERP
Risk Management

Get referred to ASSYSTEM

See people who can refer or advise you

Requirements
  • Nuclear Defence or wider Defence sector experience.
  • Experience supporting major infrastructure, engineering or nuclear programmes.
  • Experience with NEC4 contracts.
  • A proven track record of managing multiple projects for at least 3 years.
  • Knowledge of project governance and the application of project controls.
  • A solid understanding of key performance indicators and Earned Value Management.
  • Proficiency in understanding and using enterprise resource planning systems.
  • Strong experience using the Microsoft Office Suite.
  • A Project Management qualification, such as APM.
  • The role is subject to security and export control restrictions, and all applicants must achieve at least Baseline Personnel Security Standard.
  • Depending on the required national security vetting level, applicants may typically need 5 to 10 years of continuous residency in the United Kingdom.
Responsibilities
  • Deliver projects to agreed scope, quality, schedule and budget, ensuring alignment with organisational objectives.
  • Apply recognised project management methodologies and best practices across the full project lifecycle.
  • Manage project budgets and monitor financial performance to ensure successful commercial outcomes.
  • Support project assurance activities and governance reviews to maintain compliance and delivery excellence.
  • Ensure adherence to agreed client processes, procedures and contractual requirements.
  • Monitor project team performance against contractual obligations and delivery milestones.
  • Identify, manage and escalate project risks and opportunities where appropriate.
  • Build and maintain strong relationships with clients, suppliers and the wider supply chain.
  • Review and update project schedules, duration and cost estimates, identifying key milestones and critical dates.
  • Produce financial reports and maintain accurate project forecasts and final cost estimates.
  • Maintain integrity, transparency and professionalism across all project activities.
  • Assess proposed changes, evaluate their impact and obtain additional information where required.
  • Foster collaboration, teamwork and a positive project culture.
  • Support business growth through the preparation of high-quality client bids and proposals.
Desired Qualifications
  • Knowledge or experience of working within frameworks.
  • Ability to attend the Assystem Glasgow, Bristol or Newcastle offices 2–3 days per week to work alongside the project and engineering teams as required.
  • Willingness to travel to customer sites as required.

Assystem provides engineering services for complex projects, covering design, construction, supervision, commissioning, and operation, with a strong focus on the nuclear and energy sectors. Its approach combines multidisciplinary engineering teams and project-management capabilities to move projects from initial concept through to operation. The company differentiates itself through a long track record, strategic acquisitions (including Alphatem in 1995 and Mactech Energy Group in 2025) and an early public offering in 2013, which have expanded its capabilities and market reach in the energy and nuclear fields. Its goal is to be a leading, reliable partner for clients by delivering end-to-end engineering services and helping them meet safety, performance, and regulatory requirements across the project lifecycle.

Company Size

5,001-10,000

Company Stage

IPO

Headquarters

Paris, France

Founded

1966

Get referred to ASSYSTEM

See people who can refer or advise you

Simplify Jobs

Simplify's Take

What believers are saying

  • H1 2026 revenue reached €328.5 million, with 2.5% organic growth.
  • Assystem won Rolls-Royce SMR momentum, plus GBE-N, MoD, and FRAM roles.
  • Cotentin's 120 hires support Aval du Futur, targeting 10,000 jobs by 2028.

What critics are saying

  • International revenue fell 7.1% in Q1 2026, hurt by India, Saudi Arabia, and currencies.
  • Eighty-one percent nuclear concentration exposes Assystem to French and UK program slippage.
  • Wylfa SMR or Aval du Futur delays would damage backlog, hiring, and margins.

What makes ASSYSTEM unique

  • Nuclear made 81% of H1 2026 revenue, anchoring Assystem's specialization.
  • June 24, 2026 CPS2 Tier 1 status embedded Assystem in UK nuclear procurement.
  • Mactech's 2025 acquisition and 2026 Cotentin hiring deepened nuclear delivery capacity.

Help us improve and share your feedback! Did you find this helpful?

Benefits

Health Insurance

Dental Insurance

Vision Insurance

Unlimited Paid Time Off

Flexible Work Hours

Remote Work Options

Paid Vacation

Paid Holidays

Hybrid Work Options

401(k) Retirement Plan

Wellness Program

Mental Health Support

Gym Membership

Professional Development Budget

Conference Attendance Budget

Stock Options

Company Equity

Phone/Internet Stipend

Home Office Stipend

Relocation Assistance

Childcare Support

Meal Benefits

Parental Leave

Family Planning Benefits

Fertility Treatment Support

Company News

Yahoo Finance
Jul 23rd, 2026
Assystem's H1 revenue rises 2.5% organically to $371.2M on nuclear growth

Assystem reported consolidated revenue of €328.5 million for the first half of 2026, representing organic growth of 2.5% despite a 1.9% negative currency effect. The French engineering group's nuclear activities drove performance with 8.0% organic growth, accounting for 81% of total revenue. Revenue in France rose 4.2% organically to €201.1 million, led by strong momentum in nuclear new-builds and fuel cycle activities. International operations generated €127.4 million, remaining stable organically despite currency headwinds from the pound sterling, Indian rupee, and Saudi riyal. The UK showed robust growth in civil nuclear engineering and defence. However, business volumes declined in the Middle East, Central Asia region and India due to project endings and slower contract phasing. Assystem confirmed its full-year 2026 targets.

Yahoo Finance
Apr 23rd, 2026
Assystem posts $187.4M Q1 revenue with 2.2% organic growth driven by nuclear sector

Assystem, an international engineering group, reported first-quarter 2026 consolidated revenue of €165.8 million, representing 2.2% organic growth driven by strong nuclear sector performance of 8.0%. Nuclear activities accounted for 81% of total revenue, up from 76% in the prior year. French operations grew 4.4% to €102.6 million, driven by momentum in fuel cycle activities, new-builds and digitalisation. International revenue declined 7.1% to €63.2 million, primarily due to a 6.0% negative currency effect from the pound sterling, Indian rupee and Saudi riyal. The UK showed robust growth in civil nuclear engineering and defence. Assystem secured key positions on government frameworks and its client Rolls-Royce SMR signed a contract with Great British Energy for three small modular reactors.

Bdaily
Jan 30th, 2025
Assystem expands UK footprint with takeover

A global nuclear engineering firm has strengthened its UK presence with the acquisition of a specialist construction company. Paris-headquartered Assystem has… | North East | Construction | Engineering | International | Energy | Mergers & Acquisitions | Commercial Partnerships | Manufacturing & Construction |

Assystem
Jan 17th, 2024
Assystem acquires KEOPS Automation, engineering specialist in automated systems and data enhancement

Assystem, an international engineering, digital services and project management company, has acquired 100% of the shares of KEOPS Automation, a French company specializing in the integration of industrial operating platforms and the enhancement of their data (industrial OT and IT, automated systems, supervision systems, BI applied to manufacturing).

Global Construction Review
Jan 5th, 2024
France’s Assystem acquires India’s L&T Infrastructure Engineering - Global Construction Review

France-headquartered engineer and project manager Assystem has acquired India’s L&T Infrastructure Engineering, a subsidiary of the Larsen & Toubro group.