Meals made from lamb should also be tested for horse meat content amid concern that the adulteration scandal has spread beyond beef to other meats, it emerged.

The Environment Secretary, Owen Paterson, was accused by his Labour shadow of failing to act quickly enough to restore consumer confidence by setting a 10-week window for the results from widespread testing of processed-meat products to be disclosed. Mr Paterson acknowledged during a debate in the House of Commons that "too much is taken on trust" with the current meat supply chain as recriminations from the horse meat scandal continued.

Mark Woolf, a former scientist with the Food Standards Agency, urged retailers to check lamb products as well as beef to "verify" whether they were also tainted with horse meat.

The FSA earlier acknowledged that retailers will also need to test chicken and pork.

The Independent revealed in 2009 that cafes and restaurants had fallen victim of a fraud which saw chicken bulked out with illegal injections of beef and pork byproducts.