Efforts to get Project Nexus, the programme to replace the central settlement system for gas, back on track have struggled to turn the programme around and there is still “significant risk to go-live”, according to an August update.

Project Nexus has suffered years of delays and it is now being overseen by regulator Ofgem. But the latest planned go-live date has still to be finalised.

The update said “the programme continues to track ‘red’ against the planning baseline”. Current issues that are slowing delivery include problems with data compatibility and quality, defining and achieving code stability, and slow delivery of some functionality.

Testing and market trials have proceeded slower than planned.

On market trials, although participants had slightly more confidence they could complete their trials, the update said that confidence relied on ‘blockers’ in other parts of the programme being removed and noted that the rate at which trials were being completed had slowed.

The update also highlighted concerns that there “a high level of parallel activities through to the end of the year caused by the inclusion of new activities in the plan”. That could put more pressure on the timetable.