UnPS is a specialist tunnelling and underground space consultancy with a world-class record of innovation. We have been responsible for the detailed design of more than £2 billion of the most prestigious tunnelling projects in the UK.

Our team can demonstrate an unparalleled achievement in bringing new ideas to market, and we pride ourselves on seamless interfaces between tunnel design and construction that have helped deliver more than £100 million of value engineering savings to our customers.


UnPS evolved from the engineering team within Morgan Sindall’s tunnelling business, becoming an independent consultancy in 2003.

We are proud to demonstrate a world-class record of innovation, and have been responsible for virtually every significant advance in methodology and materials to the industry. These include:

  • Steel fibre reinforced tunnel linings
  • CombiShell™ method of tunnelling
  • ‘Grey Rock’ tunnel design philosophy
  • Variable diameter slipformed shafts
  • Computer-guided caisson shaft sinking
  • LaserShell™ method of tunnelling
  • TunnelBeamer™
  • MultiMode™ Tunnel Boring Machine
  • Zero-Impact aquifer tunnelling method
  • Single-pass tunnel lining system for hydraulic tunnels
  • Composite SCL system
  • Quadracurve™ shaft lining system
  • UltraShell™ tunnel lining system
  • SlipStress™ shaft lining system
  • SmartShell™ tunnel lining system

View more information on our innovations here

“We are proud to demonstrate a world-class record of innovation”


Our teams have won and been shortlisted for numerous industry awards, including the ‘Design Innovation of the Year‘ award as part of the NCE Tunnelling and Underground Space Awards 2015.


Our People

Colin Eddie

Managing Director, UnPS

An expert in the design and construction of underground structures, Colin has more than 35 years’ experience in the tunnelling industry.

A fellow of the Royal Academy of Engineering (FREng), in 2011 he successfully led (on behalf of the British Tunnelling Society) the formation of the MSc in Tunnelling and Underground Space at the University of Warwick. He actively supports the course as a member of the Industrial Advisory Panel and is a champion / lecturer of the Construction Methods module of the course. In 2015, he became Royal Academy of Engineering Professor of Innovation and Tunnelling at the university.

Stef Gmerek

Chief Engineer

A civil engineer with 29 years’ industry experience, Stef has wide-ranging expertise in multi-disciplinary projects ranging from drainage schemes to large complex Sprayed Concrete Lining projects in urban environments.

With a broad range of technical and management skills, Stef has worked in roles encompassing planning, structural design and design management, most recently as Project Design Engineer for the £235 million Crossrail C510 Liverpool Street and Whitechapel Station Tunnels project. Previously he has worked on the £38 million Thames Water Ring Main Tunnel (Brixton to Honor Oak), and the King’s Cross Underground Station Redevelopment project.

Andy Machon

Senior Engineering Manager

A chartered civil and structural engineer, Andy has 25 years’ experience working on both the design and construction elements of major, high profile infrastructure projects in the UK.

Andy has worked in a variety of roles including Section Engineer and Planning Engineer on the Thameslink rail project, Design Manager on Heathrow Terminal 5 road and rail tunnels, and Senior Engineering Manager on both the Belfast Sewers and Lee Tunnel projects. As Senior Engineering Manager he held responsibility for the delivery of the design packages and interface management with Mechanical, Electrical, Instrumentation, Controls and Automation (MEICA).