Tech giant Google is estimated to be sending over a third (36%) of its Safari advertising revenue to Apple, illustrating how far the firm is willing to go to be the go-to search engine.

The revelations were made by an expert witness testifying on behalf of Google as the Silicon Valley-based outfit defends itself in the US courts from claims that it has engineered an advertising monopoly.

The trial, which pits the US Department of Justice against Google has been ongoing since September last year, following claims by the prosecution that Google’s machinations have drastically, and illegally restricted online advertising competition.

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Google however disputes these claims, arguing that its apparent monopoly originates in the superior quality of its product. Any ruling made against Google would as a result have serious implications for the global tech industry.

Although many revelations made at the trial have been kept secret, some information has been made public. In total, Google has paid a further $26 billion (£21 billion) to a range of other companies including Apple, Samsung and Mozilla, be installed as their default search engine.

Wall Street analysts have estimated that more than $18 billion of this was sent to Apple. The judge overseeing the case, Amit Mehta, is not expected to make a ruling until early next year.