One of the food companies at the centre of the horse meat controversy is considering legal action against its suppliers.

Findus said it was looking into legal action as an internal investigation "strongly suggests" the contamination "was not accidental".

It said it carried out a full product recall on Monday, two days before tests found some of its lasagnes contained up to 100% horse meat.

It tested 18 beef lasagne products, made by Comigel, and found 11 contained between 60% to 100% horse meat.

The company said in a statement: "Findus is taking legal advice about the grounds for pursuing a case against its suppliers, regarding what they believe is their suppliers' failure to meet contractual obligations about product integrity."

Meanwhile, the French Ministry of Agriculture is to investigate how horse meat ended up in what were supposed to be beef meals produced by a French company.

A spokesperson for the Ministry said that they consider the issue a matter of criminal fraud.

Last night retailers in Sweden followed Irish and UK counterparts in withdrawing some frozen meals from shops made by the French food supplier, Comigel.

Minister for Agriculture Simon Coveney said the issue is a Europe-wide problem and what was needed is a Europe-wide response regarding DNA testing of meat.

Two ready meal ranges sold by Aldi in Britain have been found to contain up to 100% horse meat, the supermarket chain has confirmed.

The company said it felt "angry and let down" by Comigel.

Tests on Today's Special frozen beef lasagne and Today's Special frozen spaghetti bolognese found they contained between 30% and 100% horse meat, Aldi said.

Britain's Environment Secretary Owen Paterson said he was concerned that an international conspiracy was taking place.

He was speaking after attending an emergency meeting with bosses from leading supermarkets, trade bodies and the UK Food Standards Agency.

The FSA has asked all retailers and processors to test all their processed beef products to make sure they are what they say they are.

Mr Paterson said: "It's a question of either gross incompetence, but as I've said publicly and I'll repeat again, I'm more concerned there's actually an international criminal conspiracy here, and we've really got to get to the bottom of it.

"If there's a criminal act we will work with the authorities wherever they are to ensure the appropriate measures are taken".