MPs have urged the government to include small retailers in its plans to introduce a 5p charge for carrier bags in England.

In a scathing new report, the Environmental Audit Committee accused ministers of making a “complete mess of their planned carrier bags charge by making it unnecessarily complicated”.

The government’s initial announcement said retailers with fewer than 250 employees would be excluded from the charge when introduced in autumn 2015.

But the committee concluded that small retailers should be included in the scheme, with those with fewer than 10 employees given reduced reporting requirements, as in Wales.

It said the exemption for small retailers, as well as for paper and biodegradable bags, made it confusing for consumers and less effective than the Welsh scheme, where bag use has reduced by over 75%. The proposed exemptions were also potentially harmful for the recycling industry, the committee added.

The Association of Convenience Stores (ACS) has also called on the government not to exclude small shops from the scheme. A number of English retailers have voluntarily introduced carrier bag levies, with the proceeds directed towards local charities and schools.

Chair of the committee Joan Walley MP said: “Experience from Ireland and Wales shows these schemes are popular and can make a real difference. Before the government reaches the check-out with this policy, it needs to drop the exemptions and keep it simple to help shoppers to the right thing.”

ACS chief executive James Lowman said: “Retailers in Wales have seen significant benefits from the levy that has been in place since 2011, both through saving money and being able to play a greater part in their community.

“We urge the government to listen to the recommendations of the Environmental Audit Committee and ensure that convenience stores are not left out of the carrier bag charge.”