MPs have urged the government to activate the Groceries Code Adjudicator’s (GCA) power to fine major retailers found guilty of treating their suppliers unfairly.

The GCA was established in 2013 to oversee the relationship between large supermarkets and their suppliers. But the government has failed to set the level of fine the GCA can impose on retailers, even though the adjudicator has recommended a fine of up to 1% of an offending retailer’s turnover.

The Environment, Food and Rural Affairs Committee is calling on ministers to activate the GCA’s power to fine retailers before the election.

“We find it extraordinary that the government has left the Groceries Code Adjudicator for more than a year with no practical ability to use her legal powers,” said committee chair Anne McIntosh MP.

“We recommend that a statutory instrument setting out the level of fine the Groceries Code Adjudicator may levy be laid within the remainder of the present Parliament. We seek a clear explanation of why the GCA has been left so long without the teeth she needs to do her job.”

The committee is also calling for more protection for dairy farmers against rapid cuts in milk prices. The GCA can only investigate complaints involving direct suppliers to the top 10 UK retailers, so it excludes the majority of dairy farmers as most milk production is small scale.

“[The GCA’s] remit should be extended to include small-scale suppliers, whether or not they have a direct relationship with the ultimate seller of their produce,” McIntosh said.