A £27m butterfly sanctuary, which was launched by naturalist Sir David Attenborough, is to close.
Butterfly World in Chiswell Green, St Albans, opened in 2009.
The centre, which is currently shut for the winter, confirmed it would not be reopening next year and would make an official statement on Monday.
The Herts Advertiser said its chairman blamed a "succession of trading losses" in an email to "friends" of the site.
The newspaper reported chairman John Breheny wrote: "Butterfly World remains a seasonal visitor attraction, and the cumulative level of trading losses could only be sustainable whilst there was still a realistic hope that the necessary funding could be found to build the [proposed] Biome and thereby complete the project.
"Without the prospect of a viable phase four Biome, I can no longer expect Breheny employees to fund the project indefinitely without being able to promise them even the merest hope that some of the considerable investment to date and the sacrifices they have made, will somehow produce some level of reward."
The site, founded by lepidopterist Clive Farrell, housed over 600 tropical butterflies was created in the shape of a butterfly's head.
At the sanctuary's launch in 2008, Sir David Attenborough warned that three-quarters of butterfly species in the UK had declined in the past 20 years, and it was hoped the site could counteract the decline of species globally.
More sections were added to the sanctuary over the years and it became home to many rare butterflies including a half male, half female gynandromorph that was discovered just two months ago.
But plans to build a giant dome housing 10,000 butterflies never materialised.
It has not been confirmed what will happen to the existing butterflies at the centre.