The new 5p plastic bag charge will cost £1.5 billion over the next decade, with households taking a £67 hit over the period, the TaxPayers’ Alliance claim.
Ahead of new rules coming into force on October 5, the pressure group said it was “to all intents and purposes a shopping tax which will add more to the cost of living for families.”
Controversially their researchers argue it will achieve only “minimal” benefit for the environment as plastic bags account for less than two per cent of household waste and they claim people will turn to more resource-intensive bags like bin liners instead.
Their study suggests that the 5p charge will cost £1.1 billion, with substitute bags for life and bin liners costing £348 million, extra VAT £70 million and taxpayer enforcement £5m.
It comes after Ministers were criticised for making the rules on so called single use bags too complicated.
Shoppers can avoid the charge if they are carrying raw meat or fish, but the supermarket will have to charge if it is cooked.
Unwrapped blades, prescription-only medicines and woven plastic bags also escape the charge, and small and medium sized businesses will also be exempt.
Chief executive Jonathan Isaby said: “Politicians rightly identify the cost of living as a huge concern to people, yet seem oblivious to the irony that their own actions are adding to the burden.
“This appears to be a very ill-considered policy which will fail to achieve its stated aims.”
However environmentalists point to dramatic changes in shopping habits where a charge has been introduced.
Wales was the first in the UK to bring it in, followed by Northern Ireland in April 2013 and Scotland last October, where 147 million less bags were used just in the last quarter of the year.
In Wales use of plastic bags has dropped 78 per cent and 71 per cent in Northern Ireland.
Last year British shoppers took home 8.5 billion single use bags - up 200m from 2013.
A spokeswoman for Keep Britain Tidy said it wasn’t a tax as people had a choice whether to pay it, adding: “If the charge can reduce the amount used by 70 per cent of 8 billion that is a significant decrease.
“The life span of a single use bag is just 20 minutes; most people just put them in the bin, and we know they end up on the floor as litter.”
She said consumers were already used to retailers like Aldi and Lidl already charging 5p for bags. KBT would have liked the Government to have gone further and included all retailers.
The Government is expecting to see up to a 80 per cent fall in the number of plastic bags given out in supermarkets.
Charities are forecast to receive £730m from retailers, who are expected to give most of the proceeds to “good causes.”
A Defra spokesman said: “This policy will encourage shoppers to use fewer plastic bags, helping to put to an end to the blight of plastic bags littering our communities, our countryside and our marine environment.
“Shoppers won’t have to pay if they bring their own bags or purchase a ‘bag for life’, which most retailers will replace for free.”