A West Midlands aquarium business is under investigation by customs after being linked to the largest coral smuggling operation seen in the UK.

The animals, which are protected under the Convention on International Trade in Endangered Species, were discovered in air freight at Manchester airport.

HM Revenue & Customs officers working from Manchester and Heathrow airports seized the shipment containing 350 live corals and clams, including a significant number of rare corals which are banned from importation into the EU.

The market value of the coral is put at somewhere near £50,000.

The containers were shipped from Indonesia via Malaysia destined for retail traders based across the UK who had pre-ordered the creatures via one wholesaler.

Although investigators discovered the shipment in September, details were kept confidential and on-going inquiries are under way into businesses in the West Midlands, Manchester, Cheshire, Northamptonshire, Yorkshire and Scotland.

The haul involved corals falsely declared on the Customs import declaration, including corals banned in trade such as Catalaphyllia jardinei, Trachyphyllia geoffroyi and species from the genera Plerogyra.

All hard corals and giant clams are strictly regulated by the Convention on International Trade in Endangered Species (CITES).

Linda Paul, HMRC head of detection North West, said: "HMRC takes its role in enforcing international agreements and prohibitions designed to preserve our natural environment very seriously. Anyone tempted to trade in protected creatures and plants should think again. The illicit trade in endangered animals is one of the most serious global problems of our time. Not only does this crime endanger our planet, but it could mean that some animals disappear for ever."

Because of difficulties in identifying many corals to species level, experts were called in to assist officers with this task.

The corals have now been sent to London Zoo, where tanks large enough to cope with them were available.

Most of the corals and clams survived in transit and are now flourishing in a specialist aquarium, HMRC said. Charles Mackay, head of the HMRC specialist CITES team based at Heathrow said: "The vast majority of the aquarium import trade is carried out quite legitimate. However this was quiet clearly a blatant attempt to smuggle banned and unlicensed corals into the UK in order to profit from the higher prices they would fetch. HM Revenue & Customs will continue to crack down on the illegal international trade in wildlife and plants to safeguard endangered species which are threatened with extinction."

Brian Zimmerman, head keeper at London Zoo's aquarium, said: "It is disheartening to see so many protected species being smuggled into the UK. These protected species are vulnerable to over-collecting which is why their trade has been banned in the EU. It is a shame that some individuals chose to ignore laws put in place to ensure the survival of the very species they claim to admire. Most home aquarium enthusiasts would not condone this illegal trade but those that disregard the law give a bad name to the whole industry.