The Government is expected to table plans for a grocery adjudicator in the Queen’s Speech on Wednesday.

The Groceries Code Adjudicator Bill will give the watchdog the power to investigate grocers with a turnover of £1bn or more.

The adjudicator will enforce the Groceries Supplies Code of Practice, introduced two years ago, which is at present overseen by the Office of Fair Trading (OFT).

The initaitive comes after accusations from suppliers that bullying tactics by supermarkets are affecting their ability to trade effectively.

It will allow suppliers to anonymously report retailers accused of underhand tactics.

The bill has cross party support and was recommended in two reports by the Competition Commission published in 2000 and 2008.

Tesco, Asda, Sainsbury’s and Morrisons are among those that would potentially be affected.

The British Retail Consortium has questioned the need for the adjudicator, arguing that it will replicate the OFT’s role and create additional costs for retailers.