A statement from the House of Commons Environment, Food and Rural Affairs Committee said:
The evidence we received from retailers and food processors in the UK and Ireland suggests a complex, highly organised network of companies trading in and mislabelling frozen and processed meat or meat products in a way that fails to meet specifications and that is fraudulent and illegal.
We are concerned at the failure of authorities in both the UK and Ireland to acknowledge the extent of this and to bring prosecutions.
We are dismayed at the slow pace of investigations and would like assurance that prosecutions will be mounted where there is evidence of fraud or other illegal activity.
– Commons Environment, Food and Rural Affairs Committee
MPs have condemned the slow pace of the investigation into the horsemeat scandal, with no prosecutions six months after the problem was first identified.
The Commons Environment, Food and Rural Affairs Committee said the authorities in both the UK and Ireland - where horse DNA was first discovered in processed beef products - had yet to acknowledge the scale of the illegal activity involved.
The committee called for assurances that the authorities will act if evidence is uncovered to support criminal prosecutions.