British veterinary authorities have concluded that Taiwanese birds, rather than a parrot from Suriname, bought bird flu to the UK.

A government report said the mixing of tissue samples led officials to wrongly assume a South American blue-headed pionus was the source of the virus.

Opposition politicians said the report exposed confusion in the system and raised more questions than it answered.

But ministers argued it showed quarantine procedures were working.

The probe for the Department of Environment, Food and Rural Affairs (Defra) said it was more likely the virus was brought to an unnamed quarantine centre in southeast England by 50 finches from Taiwan rather than by the Surinamese parrot as previously thought.

Because the tissue samples of the first birds to die were mixed, it was unclear which birds had the highly pathogenic H5N1 virus strain.

Later tests showed the Taiwanese birds were the "most likely" virus source, as H5N1 was not found in other species.

A Mesia

The report found the highly pathogenic strain of bird flu was initially identified when tissues from two birds that had died in the centre were analysed together.

These were a blue-headed pionus from Surinam and a mesia from Taiwan, which were found dead on 14 October.

The report concludes "on the balance of probabilities" the H5N1 was brought to the facility by the mesias.

This was because later tests showed that 53 Taiwanese mesias died from the disease, but that none of the birds from Suriname had.

"It looks as if it wasn't the parrot," animal welfare minister Ben Bradshaw told a parliamentary committee. "But we will never know for certain."

The government in Paramaribo has always insisted that the parrots were disease free when they left the Caricom-member state in September.