As an Expert Witness in software litigation, computer forensics and computer criminal prosecutions, Stephen has been involved in a wide range of cases including what is thought to be the largest civil action over a software development contract to come to trial in the English High Court. This took place in 2001 when he was called as an expert witness in Airtours plc v Electronic Data Systems Limited, involving a £200m claim and £50m counterclaim.

He has been instructed as an expert witness across the world in legal actions concerning major software development contracts which have been terminated, with the software rejected amidst allegations of incomplete or inadequate delivery, software errors, shifting user specifications, poor project management, delays and cost over-runs.

Stephen has developed a range of rigorous analytical techniques for assessing and reading the 'technical entrails' of failed, stalled, delayed or generally troublesome software development projects. Stephen’s approach is particularly important where software projects involve a contractually uncertain mixture of 'customised' software packages and 'bespoke' software construction, a situation that has become increasingly prevalent.

In 2006, Stephen was appointed Chair of the London IT Planning Committee for the Avian Flu Summit.