A judge has ruled that Google ’s search engine has been illegally exploiting its dominance to quash competition and stifle innovation in a decision that could shake up the internet. US district judge Amit Mehta’s ruling came nearly a year after the start of a trial pitting America’s Justice Department against the tech giant in the country’s biggest anti-trust showdown for a quarter of a century. After reviewing evidence that included testimony from senior executives at Google, Microsoft and Apple during last year’s 10-week trial, Judge Mehta said: “Google is a monopolist, and it has acted as one to maintain its monopoly.

” Google “enjoys an 89.2 per cent share of the market for general search services, which increases to 94.9 per cent on mobile devices”, the 277-page ruling said.

It represents a major setback for Google and its parent, Alphabet , which had argued that its popularity stemmed from consumers’ overwhelming desire to use a search engine so good that it has become synonymous with looking for information online. It is likely to appeal against the ruling in a process that could go to the Supreme Court . The case depicted Google as a technological bully that has methodically thwarted competition to protect a search engine that has become the centrepiece of a digital advertising machine that generated £188 billion in revenue last year.

Justice Department lawyers argued that Google’s monopoly enabled it to charge advertisers artificially high price.