The government has denied claims it has caved in to the tobacco industry after plans to introduce plain cigarette packaging in England were put on hold.
A decision has been delayed so more time can be spent examining how similar plans have worked in Australia.
Health minister Anna Soubry said she "would never give into pressure" and awaiting more evidence was "sensible".
But Labour said it was a "humiliating u-turn" and questioned the input of Tory election strategist Lynton Crosby.
Health campaigners and doctors groups have criticised the move, which comes as the government confirmed plans to set a minimum price for alcohol in England are to be formally abandoned.
David Cameron was a vocal advocate of minimum pricing as a way of tackling drink-related health and social problems but he appears to have been defeated by ministers who feared it would not work and prove unpopular with voters.
BBC political correspondent Ben Wright suggested the Conservatives were trying to jettison potentially unpopular policies in order to focus on their core economic message in the run up to the next election.
Ministers had also been keen to go ahead with the cigarette packaging proposal, designed to discourage young people from smoking by making the packets less attractive, after the Department of Health held a consultation last year.
Under the plans, the standardised packets would all be the same colour, with the same font, and carry a prominent graphic warning.
But Health Secretary Jeremy Hunt said the government wanted to see how the policy had worked in Australia, the first country to introduce plain packaging last year, before making a "final decision".
He said a public consultation on the issue, the details of which have been published on Friday, had shown that the debate was "highly polarised" with "strong views" about the effectiveness of the policy on both sides.
In an urgent question in the Commons, shadow health minister Dianne Abbott said the "disgraceful" announcement showed the government had "caved in to big business" and the "health of the nation has been sacrificed to the interests of big tobacco".
"We have to ask on this side of the House what happened," she added. "We suspect that Lynton Crosby happened."
Mr Crosby's lobbying firm Crosby Textor was employed by British American Tobacco in Australia, but the company said the lobbyists did not work on its campaign against plain packaging there.
Asked what evidence Labour had of Mr Crosby's direct involvement, Mrs Abbott said she was not saying "he is influencing public health decisions per se" but suggested he had told senior Tories that this and other policies would give them "problems with UKIP".
But health minister Anna Soubry told MPs this was a "complete red herring" since Mr Crosby had not had any conversation with a health minister on the issue.
And No 10 said Mr Crosby had had "no involvement" in the decision and had never lobbied David Cameron on the issue.
The decision was criticised by Conservative MP Sarah Wollaston, a former GP, who said many advances in public health - such as the ban on smoking in public places - were controversial at the time but now commanded overwhelming public support.
"My view unfortunately is that it's all about election strategy, she told the BBC. "The idea that public health is something which should be scraped off the boat as some election strategists have announced I think is entirely wrong."
But Conservative colleague Peter Bone said "evidence-based" policy making was right and changes should not be "rushed through".
Cancer Research UK claimed the decision would cost lives while the British Medical Association said it was "deeply disappointing" since packaging was a "key tool" for the industry to attract young smokers.
"This is another example of a government which claims to have prioritised public health putting vested interests over those of the public," Dr Vivienne Nathanson, its director of professional activities, said.
But pro-smokers' group Forest said ministers had "listened to ordinary people" and it was good news for those who "believe in consumer freedom and are opposed to excessive regulation".
The Tobacco Manufacturers Association said the government should look at alternative measures, such as tackling the black-market trade and sales to under-aged smokers.
"Plain packaging would have been an assault on UK business in the midst of difficult economic times," it said. "Plain packs would be far easier to copy and would have therefore been a gift to the criminal gangs behind the increasing illegal trade in tobacco."
The Scottish government says it is "still committed" to introducing plain packaging and is expected to press ahead with its own plans.
The Welsh government said it was "disappointed" by the delay and would consider "the way forward" while the Northern Ireland executive said it would like to see a "UK-wide" response to the issue.