A Bristol-based company is being criticised for hosting a website known for sharing child-sex-abuse material.
Web-hosting company Zare provided its services to photo-sharing site Imgspice for four days last month.
The Internet Watch Foundation describes Imgspice as "notorious" for spreading child-sexual-abuse material.
The charity says companies such as Zare should work harder to vet customers and prevent people "profiting financially from the rape and abuse of children".
Zare says it terminated its relationship with Imgspice when it received complaints from the IWF.
Its parent company, Hydra Communications, said: "The Internet Watch Foundation (IWF) brought this to our attention on 1 June, whereupon the service and account were immediately terminated.
"Hydra Communications fully supports the IWF and we will continue to provide our complete cooperation, working together with the charity, the wider industry, and the police towards a safer internet."
Web-hosting companies such as Zare store the files that make up a website and make them available for viewing by visitors online.
Imgspice is based in the Seychelles and allows users to upload images and videos to webpages for sharing with others.
Advertising money from popular content is shared with the uploader if they receive enough views.
The IWF says the website is known to its hotline operators as a "notorious" site used by predators to share child-sexual-abuse material.
There were more than 2,500 incidents of confirmed child-sexual-abuse content on the site, last year.
And so far this year, investigators have found nearly 1,500 webpages containing child-sexual-abuse material on the site.
Most of the images or videos are of 11- to 13-year-old girls.
An Imgspice representative said it was working to improve its platform moderation and blamed the volume of illegal uploads on a possible jealous rival trying to harm its business.
Imgspice has been hosted by multiple providers in multiple countries since at least as far back as 2014, and in recent years by NForce has hosted it, based in the Netherlands.
But on 28 May, Australian authorities started receiving complaints about content found on Imgspice.
And investigators warned the IWF the site was now being hosted in the UK.
The IWF said it had then found URLs of webpages containing child-sexual-abuse content it had worked to have taken down just days earlier, when the site had still been hosted in the Netherlands.
Once the IWF had secured clearance from police, a takedown notice was issued to Zare, which acted on it extremely quickly, and, within 40 minutes, the site moved back to the Netherlands.
Previously, the proportion of global child-sexual-abuse material hosted in the UK was 0.1%.
IWF chief executive Susie Hargreaves said: "At the root of all this, someone, somewhere is profiting financially from the rape and sexual abuse of children.
"This is what is at the core of this.
"If you have a business hosting content, you need to make sure that you are not facilitating the spread of images and videos of this abuse.
"It's as simple as that.
"Companies need to be far more proactive in keeping their servers clear of this material."
NForce said it was the responsibility of its customers to monitor their own content and it was satisfied Imgspice was working hard to improve its moderation.
"IMGspice is not to be blamed here," a spokesman said
"They can't monitor all the images,.
"They are removing them as soon as they get any issues.
"And after implementing a new system to identify previously uploaded materials, this is as much as they can do."