Downing Street has criticised retailers for their apparent reluctance to publicly respond to the horsemeat scandal, which has hit many of the big supermarkets.

Unnamed Number 10 sources have said: “It isn’t acceptable for retailers to remain silent.”

But retailers said they would speak out once they had seen test results ordered by Food Standards Agency to determine the presence of horse meat in all processed beef products. The first results of those tests are set to be revealed today, said the BBC.

The sources at Number 10 said some of the big supermarkets should explain themselves, outlining how the crisis happened, how they have dealt with suppliers since the issue arose and how similar problems can be avoided in future.

“It isn’t acceptable for retailers to remain silent while customers have been misled about the content of the food they have been buying,” they said.

A spokesman for the British Retail Consortium said its members had been focusing on the swift testing of their products and would talk to the public and media about the results of those tests when they were released, the spokesman said.

He added that he was confident the results would not show a mass of new cases.

Aldi and Tesco have already withdrawn some ready meals from their shelves for containing traces of horse meat, while yesterday Asda withdrew its beef Bolognese sauce after finding horse DNA in it.

Retailers said getting through all their processed beef ranges could take several weeks.

Meanwhile, European food safety experts will meet in Brussels on Friday morning to draw up plans on how to conduct DNA testing of a large number of beef food products across much of the continent in the coming weeks.

The meeting is being held after the French government accused meat processing company Spanghero of knowingly selling horse meat labelled as beef.

The firm has denied the allegations, saying it only ever dealt in meat it believed to be beef.