Just hours after the revelation that alcohol has fuelled a 25% increase in liver deaths in the past decade, Downing Street has finally given health experts what they have long clamoured for – and what health secretary Andrew Lansley has resisted – a minimum price per unit.

Minimum pricing for alcohol has been a battleground since the election of the coalition government – and indeed under Labour, which also resisted the measure. But the battles have not just been between health experts and the industry. There have been clashes between the prime minister's office and the Department of Health (DH) as well.

The health secretary has consistently lined up with the industry on unit pricing, while David Cameron clearly indicated last month, on a visit to a hard-hit hospital in north-east England, that he thought pricing was an issue.

The drinks industry has argued that educating drinkers about the dangers of excess is enough to curb the devastating effects of alcohol abuse. But the scale of the problem – in terms of violence and aggression in city centres and the burden on hospitals – has become urgent and very visible. The industry's claim that the issue is only about a small minority of "problem drinkers" has been sounding increasingly hollow in the light of reports such as that by the National End of Life Care Intelligence Network, which on Thursday warned of rising numbers of deaths among those in their 40s.

Lansley's answer has been the "responsibility deal" with drinks companies, pubs, restaurants and supermarkets. But a number of respected health organisations, including the British Medical Association, the Royal College of Physicians and the British Liver Trust, walked out of the alcohol panel negotiations with the government and drinks industry. Talk of voluntary measures, such as numbers of units on bottle labels and awareness campaigns, was pointless, they said, if the main measure that could change behaviour was not up for discussion. That was pricing.

Lansley would not allow it and did not accept the evidence of a Sheffield University study which found that raising prices cuts drinking.

"It seems odd that Lansley is so constant on the evidence surrounding tobacco and price increases affecting consumption and fails to accept the as-strong and robust evidence on price," said Katherine Brown of the Institute of Alcohol Studies. She talks of "a tsunami of alcohol harm at the moment, caused largely by the huge availability of very cheap alcohol on supermarket shelves". Even as Downing Street was preparing to announce minimum pricing, the DH circulated a press release celebrating the latest achievements of the responsibility deal, including decisions by Sainsbury's to stock a wider selection of "lighter" wines and by Tesco to expand its range of low-alcohol wines and beers. In total, the department said, the pledges would "shed a billion units to cut hospital admissions and 1,000 deaths".

But health groups were underwhelmed. "While initially the headline appears impressive, in reality this is going to have minimum impact with a very small reduction in consumption," said Andrew Langford, chief executive of the British Liver Trust. "The pledge highlights the incredible lack of ambition from the government's Responsibility Deal Alcohol Network group and we would urge the impending alcohol strategy to tackle alcohol issues head-on rather than paying lip service to the drinks industry and supermarkets."

It appears the health lobby, boosted inside the Commons by Conservative MP and Devon GP Dr Sarah Wollaston, has finally got its way. It may also have been helped by a certain tension between different parts of the drinks industry. The pubs and restaurants have seen their trade fall off as drink has become so much cheaper, relatively speaking, in the supermarkets and off-licences. They are less opposed to minimum pricing in the hope that it will bring back some business. Pubs argue that they provide a safer drinking environment than the home, because people drink more slowly and more sociably in company – and landlords will tell them when they have had enough.

The drinks industry, however, will not be happy. A challenge to the legality of minimum pricing has already been suggested over Scotland's plans. There will almost certainly be a case brought in the European courts on a fair trading argument, but health campaigners believe it will be thrown out. EU rules, they claim, merely prevent prices being set for UK-produced drinks which are different from those imported from other countries.