The advertising regulator has banned the online dating service eHarmony from claiming it has a “scientifically proven matching system”.

Upholding a complaint about a billboard ad on London Underground, the Advertising Standards Authority (ASA) said the claim was misleading because eHarmony could not prove its service provided a greater chance of finding lasting love.

The offending advertisement, which was seen by the complainant in July last year, said: “Step aside, fate. It’s time science had a go at love.”

It went on: “Imagine being able to stack the odds of finding lasting love entirely in your favour. eHarmony’s scientifically proven matching system decodes the mystery of compatibility and chemistry so you don’t have to.”

The ASA said the words suggested scientific studies had demonstrated that the website offered users a significantly greater chance of finding lasting love than if they did not use the service.

It said there was no proof people were any more likely to meet partners through the eHarmony website than by other means, online or offline, such as social networking, at work, through friends or in a bar or club.

David Lipsey, joint chair of the all-party parliamentary group on statistics, who lodged the complaint, welcomed the ASA ruling. “Phrases like ‘scientifically proven’ should be confined to claims that are just that, not used in crude puffery designed to lure in those longing for love,” said Lord Lipsey, a former lay member of the ASA’s council. “This is a new form of fake news which the ASA has rightly slapped down.”

Founded in the US in 2000, eHarmony expanded into the UK in 2008. It uses a closely guarded compatibility matching algorithm to pair users, and requires them to complete lengthy relationship questionnaires to determine their personality traits, values, interests and other factors.

In its defence, it told the ASA the algorithm was based on data collected from more than 50,000 married couples in 23 different countries, which it said resulted in statistical models yielding cut-off thresholds for scores indicating a high probability of successful relationships if married. It claimed it was based on “scientific theories in the relationship literature of assortative mating”, the ASA said.

The dating service submitted copies of two published studies that reported higher levels of marital satisfaction for couples who met through eHarmony than any other offline or online methods. But the ASA found that the results of the studies did not justify using the words that were the subject of the complaint.

It said in its ruling: “Both studies did not reveal anything about the percentage of the overall users of eHarmony who had found lasting love after using the website compared to other sources. Therefore, neither study provided insight into the likelihood of the website finding users lasting love compared to users who did not use the service.

“Because the evidence provided by eHarmony did not demonstrate that their matching system offered users a significantly greater chance of finding lasting love than what could be achieved if they didn’t use the service, we concluded that the claim ‘scientifically proven matching system’ was misleading.”

Romain Bertrand, the managing director of eHarmony UK, said: “Although we respectfully disagree with the ASA’s findings, we are happy to work with them to assure that our advertising is as clear as possible.”

In 2009 the ASA found that an eHarmony television advert stating that 2% of newlyweds in the US said they had met through its service was misleading because it was extrapolated from an online survey but gave the impression it was a definitive figure.