THE UK Government will move to block meat imports if contaminated burgers and ready meals are found to contain horse meat from animals treated with a banned drug.

Environment Secretary Owen Paterson said he would take the necessary action if tests reveal use of the veterinary drug phenylbutazone, or "bute," which is not permitted to enter the food chain.

He rejected calls for an immediate imports ban, saying it was not allowed under EU rules as horse meat found in a range of products since the start of the scandal was not considered a threat to human health.

But he said tests would continue and warned: "If they find there is a product which could potentially be injurious to public health, emphatically, I will take the necessary action."

He added: "This is a conspiracy against the public. Selling a product as beef, and including a lot of horse in it is fraud.

"It looks as if the problem is limited to processed food and it looks as if there has been criminal substitution of beef with horse. If there's a criminal act we will work with the authorities wherever they are to ensure the appropriate measures are taken."

Results of the latest tests, ordered by the UK-wide Food Standards Agency watchdog, will be published on Friday.

Mr Paterson's comments came as the focus of inquiries switched to Romania.

Findus, which has taken its beef lasagnes off shelves after some were found to have up to 100% horse meat in them, said it was considering legal action against a French supplier after internal investigations suggested the contamination was not accidental.

However, the supplier, Spanghero, based in southern France, claims it was the victim of fraud and intends to sue its Romanian supplier. The Romanian Government yesterday launched a probe into the claims. There are 25 abattoirs in Romania licenced to slaughter, butcher and export horse meat.

Tesco, Lidl, Aldi and Iceland have all withdrawn products from stores across the UK since horse meat was found in popular products. Six French supermarket chains have also withdrawn ready meals from Findus and Comigel, which supplied the Findus-branded beef lasagne.

Meanwhile, the minister responsible for food standards in Scotland, Richard Lochhead, faced calls to make a statement to Holyrood on the growing horse meat scandal.

Green and Labour MSPs called on the Rural Affairs and Environment Secretary to update Parliament on ongoing investigations, stand up for Scottish producers and provide information to consumers.

Green MSP Alison Johnstone said: "The meat scandal continues to grow and the public and Scottish meat producers deserve a clear statement in Holyrood from the Scottish minister for food. Last summer, he promised a beefed-up food standards agency for Scotland, but more beef is exactly the opposite of what we seem to be getting."

Labour's Claire Baker said: "Richard Lochhead is either sleeping on the job or is happy to hide behind the UK Government. Producers and consumers deserve better leadership from the Scottish Government."

Mr Lochhead discussed the scandal with Mr Paterson yesterday. He said: "We agreed the issue surrounding horse meat remains one of mislabelling and potential fraud with there being no evidence of any implications for human health. It is unacceptable that consumers are being misled and this cannot be tolerated.

"Given that the relevant labelling regulations are set at EU level, I discussed with Mr Paterson the need to fully engage the European Commission."

He added: "I urge customers to look for the Scotch label to ensure they are able to enjoy some of the best meat products in the marketplace."