It's been argued in real ale circles that the aggressive takeover policies pursued by Greene King and Wolverhampton & Dudley should not be opposed too vigorously as both companies are committed to cask beer production.
In the 1970s, the same argument could have been advanced as the Big Six national brewing groups were stitched together. Four of the six, Allied, Bass, Courage and Whitbread produced huge amounts of cask ale, far more than Greene King and W&D today.
The Campaign for Real Ale (Camra) vehemently opposed the mergers in the 1970s on the grounds that the new giants would phase out small volume beers in favour of national brands and would eventually supplant cask ale with keg beer and lager. Above all, Camra said, brewing groups that act as a national monopoly are bad for drinkers' choice.
The campaign was right. The Big Six axed half the brands they acquired in takeovers. They concentrated on pressurised beer and sidelined even great ales such as Draught Bass and Burton Ale. In the fullness of time, most of the Big Six disappeared, leaving such remnants as Courage and Tetley's in the hands of S&N and Carlsberg.
The same market forces will bear down heavily on Greene King and W&D as they get ever bigger. This is especially true of Greene King as a result of its takeover of Belhaven of Scotland.
Belhaven, unusually for a Scottish brewery, has a substantial estate it's these 260 pubs that attracted Greene King's interest, not the Dunbar brewery.
But the Scottish beer market is radically different to the English one. Greene King would dearly love to flood its new Scottish pubs with IPA, Abbot and Old Speckled Hen. But the strategy may not work. Belhaven is revered in cask-beer circles for its 80 Shilling Ale, but in reality it produces only tiny amounts of cask. Most of its production is in keg form.
Scottish drinkers in Belhaven bars will expect to continue to drink Belhaven Best and may not take kindly to English implants. Greene King will face a major problem with its own IPA: it will go head-to-head with Scotland's leading cask beer brand, Caledonian Deuchars IPA, which is promoted neither as 'real or 'cask and is served several degrees colder than English cask beer.
I suspect that Greene King will keep the Belhaven brewery open. It will soon need extra capacity, and it makes little sense to trunk 'Belhaven beers from Suffolk to Scotland.
Inevitably, Greene King will rapidly become a major brewer and retailer of keg beer in Scotland. The dubious benefits of keg ease of handling and long shelf life will not be lost on the accountants and sundry bean counters at Bury St Edmunds.
In the longer term, both Greene King and W&D will face the same challenges that led to the demise of most of the former Big Six national groups. The new nationals' size and ownership of large amounts of tempting real estate could make them takeover targets. With the safeguards of the Beer Orders swept away ironically by a Labour government there is little to stop both Greene King and W&D falling into the clutches of even bigger brewing groups, as long as they stay within the competition authorities' guidelines on market share.
The omens are not good. All the old problems of the 1970s and 80s could reappear: fresh mergers and takeovers at the top of the industry, fewer brands, less choice for drinkers and a move away from cask to keg beer.
It is not too late for Greene King and W&D to learn the lesson that big fish in small ponds tend to get swallowed by marauding sharks. In attempting to stop the growth of the two brewing groups, we will help them to survive.