Yvonne Hobbs is said to have launched multiple complaints against the Prime Minister and public institutions – often sending copies of her complaints to the Queen, the BBC and Parliament.
The reports raised questions about how the claim was approved by the Small Claims Court online, when libel cases are typically handled by senior High Court judges.
It later emerged that No.10’s attempt to overturn the judgment had been successful, after District Judge Hammond considered an application on Thursday.
A court official confirmed that there was no more county court judgment in the case, but declined to provide further details.
The ruling – made six months ago – had appeared to be a further embarrassment for Mr Johnson if he faces multiple inquiries from standards watchdogs.
The Election Commission is investigating who originally paid for the renovation of his apartment – while the Parliamentary Commissioner for Standards is investigating a £ 15,000 luxury Christmas holiday in the Caribbean.
But Downing Street was convinced that an application to quash the judgment on the debt would be successful, calling it “completely unfounded”.
Legal experts have suggested it was a “default judgment,” rendered when a person failed to present a defense against the complaint against them.
Usually, they are sent by post, with three different correspondences – including a letter before the claim, a final request, and then a court claim form.
But it appears the correspondence was sent to 10 Downing Street rather than any property owned by Mr Johnson, or 11 Downing Street, where his apartment is located.
A file shows that the complaint was made by a Yvonne Hobbs against “the Right Honorable Boris Johnson”, the reasons given being “defamation” and “repeated defamation”.
Under Small Claims Court proceedings, anyone can formally ask another person or business to pay them the money owed, paying as little as £ 25 for an online claim.
A spokesperson for No 10 said: “A request to set aside the default judgment, set aside the default judgment and a declaration that the claim is totally unfounded will be sought.”