Critics of the UK's sugar tax say it will burden poor people and doesn't properly account for the actual make up of drinks.
The UK TaxPayers' Alliance wants the new tax to be dumped after finding many sugar laden milk-based and iced coffee drinks will avoid the tax, while fizzy soft drinks and energy drinks won't.
The alliance compared 49 different drinks and found that Coca-Cola, with 10.6g of sugar per 100 millilitres, will be taxed, while a Starbucks hot chocolate with whipped cream with coconut milk, which has 11g of sugar per 100 millilitres, will not.
The study also found energy drinks such as Monster Ori.gin, 11g/100ml, will be taxed, but Tesco chocolate flavoured milk, 12.4g/100ml, won't be.
In all, the 10 most sugary drinks analysed by the TPA will not be subject to the tax.
"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," TPA chief executive Jonathan Isaby said.
But a UK Treasury spokesman said: "The soft drinks industry levy is a major step forward in our efforts to tackle childhood obesity. Treating obesity and its consequences costs the taxpayer 5.1 billion every year."
