The Government has denied reports that it is considering introducing a tax on sugary drinks in a bid to curb the obesity crisis.
Prime Minister David Cameron is known to be against the tax, with Downing Street saying he believes there are "more effective ways of tackling" the growing problem.
A report in the Times said a tax on sugary drinks is being considered by ministers in a U-turn amid mounting evidence it could work.
But a spokeswoman for the Department of Health said: "The Government position has not changed and we have no plans for a sugar tax."
Cancer Research UK has called for a tax on sugary drinks for the first time in a bid to curb rising rates of cancer caused by people being overweight.
A study published in the British Medical Journal (BMJ) also shows that a sugary drinks tax in Mexico has led to a 12% reduction in sales and a 4% increase in the purchase of untaxed drinks one year after it came in.
From January 1 2014, Mexico implemented an excise tax of 1 peso per litre on sugar-sweetened beverages.
Researchers in the US and Mexico examined data from more than 6,200 Mexican households across 53 large cities, and discovered a drop in people consuming sugary drinks.
They found a rise in untaxed drinks sales, mainly due to more purchases of bottled plain water.
A controversial report from Public Health England published in October said a sugar tax of 10% to 20% could work alongside other strict controls, including a ban on advertising unhealthy foods during "family" TV programming such as the X Factor.
Sarah Wollaston, chairwoman of the Commons Health Committee, told the Times: "I don't think that there's a closed door - it just needs enough people to make the case.
"So many people have come out in favour and I think there's a real momentum about this. There's a realisation that the public aren't opposed to this because they are more worried about childhood obesity."
She added: "We should start calling it a sugary drinks tax - if you call it a sugar tax it makes people nervous - and the advantage of a sugary drinks tax is that you can completely avoid it because there are directly equivalent products that aren't stuffed full of sugar. Nobody has to pay it, so it's not regressive."
She said the 5p charge for plastic bags had shown the power of small measures to change habits, adding: "This is something that could happen overnight. It's a quick win and it has a halo effect in terms of reminding people of the dangers."
Gavin Partington, director-general of the British Soft Drinks Association, said: "The soft drinks tax in Mexico has reduced average calorie intake by just six calories a day and sales in France are back to pre-tax levels.
"By contrast, the soft drinks industry is taking practical steps to help consumers, through reformulation, smaller portion sizes and increased promotion of low and no-calorie options."