Coleen Rooney has claimed to have caught another footballer’s wife passing her private information to the Sun, after apparently running an elaborate sting operation that involved placing false stories in the tabloid newspaper.

Rooney, an online influencer who is married to the former England international Wayne Rooney, said she was forced to act after a series of posts on her private social media account appeared in the media. She has publicly accused Rebekah Vardy, the wife of fellow England footballer Jamie Vardy, of being the individual who was leaking the private information.

Vardy, a former contestant on I’m a Celebrity … Get Me Out of Here!, has denied any involvement and suggested someone else may have had access to the password for her Instagram account. On Wednesday evening a tweet from the broadcaster Victoria Derbyshire said that Vardy, who will appear on her BBC2 show on Thursday, had instructed lawyers to carry out a “forensic investigation” on her Instagram account to see who has had access to it and when. The Sun has not disputed Rooney’s suggestion that Vardy was the source but amended all the disputed stories on its website to note that they could have been fabricated.

Facebook Twitter Pinterest An article in the Sun that Coleen Rooney claims she fabricated on her Instagram stories page. Photograph: Jim Waterson/The Guardian

Rooney said in a statement: “For a few years now someone who I trusted to follow me on my personal Instagram account has been consistently informing the Sun newspaper of my private posts and stories. There has been so much information given to them about me, my friends and my family – all without my permission or knowledge.

“After a long time of trying to figure out who it could be, for various reasons, I had a suspicion. To try and prove this I came up with an idea. I blocked everyone from viewing my Instagram stories except one account. (Those on my private account must have been wondering why I haven’t had stories on there for a while.)

Coleen Rooney (@ColeenRoo) This has been a burden in my life for a few years now and finally I have got to the bottom of it...... pic.twitter.com/0YqJAoXuK1

“Over the past five months I have posted a series of false stories to see if they made their way into the Sun newspaper. And you know what, they did! The story about gender selection in Mexico, the story about returning to TV and then the latest story about basement flooding in my new house.

“It’s been tough keeping it to myself and not making any comment at all, especially when the stories have been leaked, however I had to. Now I know from certain which account/individual it’s come from.

“I have saved and screenshotted all the original stories which clearly show just one person has viewed them. It’s … Rebekah Vardy’s account.”

In response, Vardy said she had never spoken to journalists about Rooney, even though many had called her.

She also appeared to imply that her Instagram account may have been improperly accessed by a third party: “If you thought this was happening you could have told me and I could have changed my passwords to see if it stopped.

“Over the years various people have had access to my Insta and just this week I found I was following people I didn’t know and have never followed myself. I’m not being funny but I don’t need the money, what would I gain from selling stories on you? I liked you a lot Coleen and I’m so upset that you have chosen to do this, especially when I’m heavily pregnant. I’m disgusted that I’m even having to deny this.”

Although the Sun has yet to formally comment on the claims, in an article on its own website the news outlet emphasised it had acted in line with standard journalism practice. “Each of the stories provided to the Sun was put to Coleen’s representatives before publication, and on each occasion they declined to comment,” it said.

Outlets including MailOnline, the Mirror, and Metro.co.uk, which had rewritten the Sun’s original stories for their own websites, have removed or heavily rewritten their articles. The most recent disputed story was published in the Bizarre column for Wednesday’s edition of the Sun, claiming that the basement of the Rooneys’ new house had been flooded. The article quoted a “source close to the couple” as complaining about problems with water ingress.

The claims come at an awkward time for the Sun, which is already facing a legal case from Prince Harry against its publisher, News Group Newspapers, for alleged phone hacking. It has also had to deal with a hefty pushback against its decision to investigate the family background of the England cricketer Ben Stokes.

Public records show that Vardy has previously provided the Sun with articles. In 2017 her agent approached the newspaper’s Sunday edition to offer an interview about her past relationships which was promoted on the newspaper’s front page, according to a subsequent complaint filed with press regulator Ipso.

She previously sold a story to the News of the World in 2004 about her brief relationship with the singer Peter Andre, although she has since insisted she was coerced into doing so.

How Rooney claims to have snared Vardy

Coleen Rooney, like many celebrities with substantial online profiles, maintains a second secret Instagram account where she posts personal pictures and updates on her family life. This was set to private, so only people approved by Rooney could follow her and read updates – essentially creating a safe environment on the photo-sharing social network where she could share posts to a trusted group of acquaintances without the general public being able to see.

Earlier this year Rooney publicly complained that the Sun was writing stories based on information she had posted to this private Instagram account – suggesting that one of these supposedly trusted acquaintances was passing information to the newspaper.

According to Rooney, she decided to root them out by posting fake updates about her life to see whether they ended up as articles in the Sun. When they did, she took advantage of an option that allows a user to limit the audience for an Instagram Stories update to a select group of users. Rooney continued to share fake updates, some of which then ended up in the Sun, as she narrowed down the potential suspects. At this point only Rebekah Vardy was able to see the updates, prompting Rooney to post one final fake update which duly appeared as a story in the newspaper on Wednesday morning. She swiftly went public with the story, earning the nickname “Wagatha Christie” for her investigative skills.

For her part, Vardy insists that other individuals have had access to her Instagram account and could be responsible.