Three people have been arrested in the Netherlands and 15 companies raided in a Europe-wide investigation into the sale of illegal horse meat.

In particular, attention has been focused on a company in Limburg which is suspected of forging horse passports, allowing horses which were not considered fit for human consumption to end up in the food chain.

Horse passports include records of all medicines given to the animals but the Limburg company is said to have supplied documents with all this information removed, the Dutch public prosecution department said.

In total 26 people have been arrested across Europe in connection with the investigation into illegal meat trading. It began in 2012 in Belgium and then spread to the Netherlands, Ireland and France.

The gang is thought to have sold at least 4,700 horses which were not considered fit for human consumption to meat processors and traders.

Officials also seized €37,000 in cash, more than 800 horse passports, as well as medication, dozens of microchips and computer equipment.