Only Monroe gave evidence at the trial, as Hopkins relied on two witness statement made by her solicitor, the judgment said.
Monroe had sued Hopkins over two tweets published in 2015, saying that the tweets accused Monroe of vandalising a war memorial or, at the very least, of approving or condoning such behaviour. Monroe argued that the tweets were defamatory and caused serious harm to reputation.
The tweets were published by Hopkins who had mistaken Monroe for Laurie Penny, a columnist for the New Statesman. In response to the vandalism of Memorial to the Women of WWII in Whitehall, London during an anti-austerity demonstration, Penny had tweeted that she did not "have a problem" with such vandalism.
In an ensuing exchange of tweets, Hopkins sent a tweet to Monroe saying: "Scrawled on any memorials recently? Vandalised the memory of those who fought for your freedom. Grandma got any more medals?"
In a later tweet, Hopkins said: "Can someone explain to me – in 10 words or less – the difference between irritant @PennyRed and social anthrax @MsJackMonroe."
Monroe said during the trial that despite her general support for anti-austerity groups, "as a proud member of a military family and a feminist" she flatly opposed and was "sickened" by the vandalism.
The judge concluded that is it "an inescapable conclusion that the ordinary reasonable reader of the first tweet would understand it to mean that Ms Monroe 'condoned and approved of scrawling on war memorials, vandalising monuments commemorating those who fought for her freedom'."
A proportion of readers of the second tweet would read it in the context of the previous innuendo and take the same meaning from it, the judgment found.
The £24,000 award is divided into £16,000 for the first tweet and £8,000 for the second tweet, because the majority of the harm to reputation will have been caused by the first tweet, and it was that tweet that caused the greatest injury to feelings at the time, the judgment said.
Litigation expert Michael Fenn of Pinsent Masons, the law firm behind Out-Law.com said: "The judgment shows that tweeting from the hip can be an expensive endeavour, and is a blow to those who had hoped that the additional requirement for claimants to establish serious harm introduced under Defamation Act 2013 would have a chilling effect on defamation actions."
"The case provides further guidance for legal practitioners as to what constitutes serious harm, namely that serious harm does not have to be ‘very serious’ or ‘grave’," Fenn said.
"The observations also show the importance of parties facing a defamation claim with merit to act quickly in retracting any defamatory tweets, apologising and/or making a suitable offer to amends under the Defamation Act 1996," he said.
Expert in corporate reputation management Imogen Allen-Back, also of Pinsent Masons said this is an "important, and claimant friendly, judgment on the meaning of serious harm under the Act".
"It also serves as a useful reminder to Twitter users that defamatory tweets can results in claims being brought against them, resulting in significant damages and costs penalties being awarded against them," Allen-Back said.
"There has been some debate about the extent to which a claimant is required to prove that he or she has suffered, or is likely to suffer, serious harm as a result of the publication complained of. In this case, the judgment said that though Monroe may not have proved that her reputation suffered gravely, the judge was satisfied that she had established that the publications complained of caused serious harm to her reputation."
"This reinforces the judge's earlier decisions that serious harm can be inferred. Although the first tweet only appeared on Hopkins feed for a couple of hours, the fact that she had a large number of followers was likely to be a significant factor affecting the decision that it met the serious harm threshold," she said.