In a submission to HM Treasury's review of alcohol taxation and pricing, the Smirnoff maker's suggestion this week, that all types of alcohol should be taxed at the same rate per unit, would add 54p to the price of a 12.5% bottle of wine, £1.85 to a two-litre bottle of Strongbow cider, and 22p to a 660ml bottle of 5.0% lager, such as Stella.
But under Diageo's proposals, spirits would be held at the current rate of 22.3p per unit, or £8.92 per litre.
It would be the "fairest and most transparent way" to tax alcohol, added GB managing director Simon Litherland.
"Alcohol is alcohol and we believe people should know they are paying the same tax per unit whether it is a pint of Guinness, a glass of Blossom Hill or a glass of Johnny Walker," he said. It also proposed setting a wine unit duty rate based on 12.5% abv, and used this measure to calculate that the proposal would generate between £524m and £1.9bn a year for the Treasury.
"I was pretty shocked when I saw the proposal," said Molson Coors managing director Mark Hunter. "Diageo's business is fundamentally spirits-based. My hunch is that a view has been taken there based on 'where do we want to orientate the market?' But why should we use tax to incentivise drinkers towards higher-alcohol products which this would do?"
Diageo's suggestion would discourage consumers from drinking low-strength products such as beer, the British Beer and Pub Association added.
The distance between duty on beer and spirits should actually increase, rather than be equalised, it suggested, because beer was more costly to produce, meaning profit margins were lower.
A senior wine industry source added that the proposed measures could potentially harm the wine industry and made "no sense" coming from Diageo, which owns the UK's bestselling wine in Blossom Hill.
A senior drinks industry source added, however: "Diageo is willing to make Guinness and Blossom Hill the fall guys in its proposals because it's making no money in these areas."