Google attacked the European Union for basing its record-breaking €2.4bn (£2.1bn) penalty in June against the search-engine giant on untested antitrust theories and ignoring the competitive pressure exerted by the likes of Amazon and eBay.

Google contends that a fine “was not warranted” on grounds that the European Commission put forward a novel theory and previously signalled the case could be solved without a financial penalty by initially seeking an amicable solution with the Alphabet unit.

The details of Google’s court appeal at the EU’s Luxembourg-based General Court were revealed Monday in the bloc’s Official Journal.

Google also said in its appeal that the commission “fails to take proper account of the competitive constraint exercised by merchant platforms” in its decision to fine the Mountain View, California-based firm for abusing its market power to edge out smaller shopping search rivals.

After losing its biggest regulatory battle yet, Google is bringing the matter to EU courts in a legal challenge filed in September that could take years to conclude.

Intel waited eight years for a ruling on its legal challenge to a €1.06bn fine in 2009 only to be told last month that the General Court must re-examine the case.

EU Competition commissioner Margrethe Vestager took over the Google probe in 2014 from her predecessor, Joaquin Almunia, who had sought to finalise a settlement with Google but failed to reach a satisfactory accord as his term came to an end.

The deal would have included binding concessions from Google in exchange for the EU dropping the probe without levying any fines.

The commission said in a statement on Monday that it “will defend its decision in court.”