Murphy’s Irish Stout is back on Wetherspoons bars across Great Britain at an average price of £2.99 a pint, placing it well below Guinness at roughly £3.50 to £5.94 across sites. While a value stout arriving in a value-led pub chain signals how squeezed drinkers have become, it also presents a critical strategic question: does a cheaper pint expand the category profitably, or simply erode till receipts? To quantify the commercial reality behind the headlines, EPIC conducted a choice-based study with 260 Wetherspoons draft drinkers, testing 16 products across regional price ladders to model 3,120 individual pint choices.

The data shows that while Murphy’s successfully expands stout occasions by 5.2 percentage points and boosts stout revenue by ~13% in London, total draft revenue actually slips by ~1.7%. This dilution occurs because Murphy’s draws most of its volume from higher-margin, faster-pouring lager rather than directly from Guinness. For Wetherspoons, the relisting generates category growth but creates a margin headwind as sales shift into a slower-pouring, nitrogenated stout with higher service costs. Meanwhile, Heineken underpriced Murphy’s at launch, as choice modeling indicates the brand could have carried £4.49 in London with minimal loss of market share.

For Diageo, the loss of ~2.6 share points in London represents a steady erosion rather than a collapse. Crucially, the model reveals that discounting Guinness to £4.99 fails to dislodge Murphy’s, drawing volume back from lager instead. Rather than triggering a margin-diluting price war, Diageo’s optimal defense relies on brand loyalty, ritual, and introducing smaller serve formats to hit accessible price points without lowering the pint price.