The first test of the UK’s new porn age-verification system can be circumvented in less than two minutes using a simple Google search, the Guardian has found, amid concerns the system is being implemented for political reasons before it is ready.

Providers of legal pornography will be required to implement an age-verification system by 15 July, one of the first of its kind in the world, raising concerns from privacy campaigners.

The system was tested for the first time last week by Channel 4, who created an “ethical” pornographic film called I Want Fourplay made by a group of mothers as part of the channel’s Mums Make Porn documentary.

Despite this, the Guardian was easily able to register and age verify an account with the email address IAmUnder18@mailinator.com in a matter of seconds by generating a non-existent credit card number, raising questions over whether it can actually stop children from accessing inappropriate material. The Guardian is excluding details of how to generate the numbers.

Channel 4 linked to a standalone website which voluntarily chose to implement one of the competing age-verification systems, ahead of the law being fully implemented. It was provided by AgeChecked.com, who describe themselves as the “global age-verification specialists”, who had hailed the success of the Channel 4 experiment as proving the system worked by requiring that people provide a form of ID, an age-verified telephone number, or a credit card.

When told about the loophole discovered by the Guardian, AgeChecked’s chief executive, Alastair Graham, said it was a first “dry run” and said he would be raising the issue with the regulator: “That’s quite interesting … That’s within the capabilities of someone relatively young. I think we’re going to swap that method out.”

He also said his site was following guidelines from the regulator on the appropriate intrusiveness of age checks, emphasising that the aim was to stop young children inadvertently stumbling across material: “We’re not taking judgement calls on how robust it should be. If the regulator said they wanted your inside leg measurement and your DNA we could.”

“All of us want more clarity on what is and what is not the correct level of robustness. We’ve been given steers but nothing solid. There is, to be frank, a certain level of frustration with the extent things are getting to the date without clarity.”

Although the legislation underpinning the age-verification system has been in place for several years, its implementation has been repeatedly delayed amid technical difficulties, while the government has had to deal with a late surge of interest in the topic as the public belatedly realise what is involved.

Age-verification websites were only told last Friday that the government would be adding new guidelines on ensuring user privacy at the last minute, following concerns from privacy campaigners, despite the policy having first been proposed by David Cameron in 2013.

The British Board of Film Classification will be responsible for vetting competing age-verification providers, but Graham said the earliest they would accredit providers would be the start of July, just two weeks before the legal implementation date, creating further uncertainty.

When it was suggested that BBFC was not ready for its new role overseeing age-verification systems, Graham said: “That would be a conclusion that you could make. I would like to maintain our positive engagement with them.

“There’s two parts to what the regulation is: it’s trying to make sure that anyone who hasn’t been age verified doesn’t see a site that’s pornographic. Then there’s the responsibility to put an age gate in place for the adults coming through. The first one is BBFC territory. The second part is very technical.”

The implementation date for the new law means age-verification providers are now rushing to promote their rival products, with some talking of a potential market of around 20-25m Britons who will want to verify their identity to access online pornography. Some of them offer verification through physical “porn passes” bought at newsagents, while others have promised to age people accurately from a selfie.