After years of mergers, acquisitions and the strong growth of new entrants, Ofgem finally decided to ditch the term ‘big six’ in November, with suppliers now being ordered by size as small, medium and large. The retirement of the big six term – with all its accompanying baggage – has been long debated. But, with Bulb and Octopus now classed in the same category as British Gas, Adam John asks whether the moniker ‘challenger’ has also had its day.