The Treasury has dismissed claims the sugar tax would amount to an arbitrary burden on the poor and took no account of the actual make-up of drinks. The Tax Payers' Alliance had said some beverages laden with sugar would be exempt from the levy.
The TPA had called for the scrapping of the budget measure after it carried out a comparison of 49 different drinks across three areas: fizzy and energy drinks to be taxed, milk-based beverages, and coffees, that would not.
According to the survey, Coca-Cola, with 10.6 grams of sugar per 100 millilitres, would be subject to the levy, but a Starbucks signature hot chocolate with whipped cream with coconut milk, which had 11 grams of sugar per 100 millilitres, would not. In all, the 10 most sugary drinks analysed by the TPA would not be subject to the tax.
TPA chief executive Jonathan Isaby said, ''It is deeply concerning that the Government has given in to the pressures from the public health lobby and is pushing ahead with this regressive tax which will hit the poorest families hardest.''
He said, ''The evidence shows that the sugar tax has nothing to do with the sugar content of products, so it is farcical to suggest that this will have any positive.''
The Treasury maintains that the tax was a "major step forward" in the fight against childhood obesity, and the money raised would fund more school sports and expanding school breakfast clubs.
The TPA study points out that energy drinks like Monster Origin, 11g of sugar per 100ml, would be taxed, but Tesco chocolate flavoured milk, 12.4g/100ml, will not be.
The 10 most sugary drinks analysed by the TPA would not be subject to the levy.
Isaby told Sky News the policy has "descended into farce".
He added: "It (the results of the study) suggests to us the Government has not thought through this proposal whatsoever, we're calling for them to scrap it.