Google is facing a fine of up to £4billion as Europe prepares to file a high-profile anti-competition lawsuit against the internet giant. The EU has been investigating the US search engine for five years following complaints that it abuses its dominance in the continent - but proceedings have stalled on three previous occasions. Now the European Commission, the EU's top antitrust authority, is asking companies who previously filed confidential complaints against Google for permission to publish them, so that officials can begin to build a case against the firm. If found to have been behaving unfairly, Google could be fined ten per cent of its annual revenues, which would be more than £4 billion based on last year's performance. Facing huge fine: Google is facing a fine of up to £4billion as Europe prepares to file a high-profile anti-competition lawsuit against the internet giant . Shopping, comparison and travel companies are among those that have been contacted by the EU, The Wall Street Journal reports. US companies Microsoft and Trip Advisor are among those that have filed complaints against Google with the EU. A decision to file charges would kick start the EU's most prominent antitrust suit since its ten year-long campaign against Microsoft Corp. - the firm was forced to pay out more than a £1billion in fines in 2012. The specific document the EU is said to be preparing is referred to as a Statement of Objections. Once filed, it's likely that a number of deeper investigations, counter-statements, and settlement discussions would ensue. If the search engine and the EU cannot come to an agreement, then fines could be issued and restrictions placed on Google's behavior. Leading investigation: New EU antitrust chief Margrethe Vestager has suggested she favours pursuing legal action against Google over pushing for a settlement . The company would then have the right to appeal the case to the highest European court. Even if it is settled without a huge fine, antitrust cases can be hugely disruptive for firm, as Microsoft discovered. The European Commission has also been investigating whether Google has been 'scraping' content from rivals' sites, and placing unreasonable restrictions on advertisers and software developers who do business with them. A 'preliminary view' taken by the commission in March  2013 was that Google was abusing its dominant position in a number of areas . The company has denied any wrongdoing. Speaking in Berlin last week, Kent Walker, the company's Senior Vice President & General Counsel, highlighted the 'painfully long list of unsuccessful Google products', including Google+ and Street View in Germany, as proof that competition laws were serving their purpose. Long-running dispute: Former EU antitrust chief Joaquin Almunia, above, made three unsuccessful attempts to resolve the dispute between Google and its European rivals . The EU's investigation of complaints that Google abuses its dominance of the online search market to hurt rivals began in 2010. The US company handles more than 90 per cent of Web searches in Europe - considerably higher than its share of the US market. Comparison-shopping sites claim that when consumers use Google to search for products online, Google positions results from Google Shopping prominently. The argument is that this relegates products from rival sites to positions lower down the search page, where they might not be seen. Margrethe Vestager, the EU's new antitrust chief, has  suggested she will pursue legal action rather than seek a settlement. Google and Commissioner Vestager’s predecessor, Joaquin Almunia, made three attempts to resolve the dispute, but in each case intense pressure by national governments, Internet rivals and privacy advocates scuppered the effort. The latest settlement proposed by Mr. Almunia fell apart following a series of interventions by powerful political players, including a letter from the economy ministers of France and Germany calling for greater concessions from Google, and protests from German publishing houses. In November the European Parliament passed a resolution calling for a possible breakup of Google, brushing aside an unusual series of objections from the US Congress that the move risked politicizing an antitrust investigation. Ms. Vestager met a month ago with Eric Schmidt, Google's executive chairman. Last week, she indicated that her priority was to ensure that smaller Internet firms could compete with the industry's giants.
EU has been investigating the US search giant's practises for five years .
3 previous attempts to settle matter have stalled due to political pressure .
One complaint is that Google Search leads users on to the firm's own sites .
Current case could result in Google being fined 10% of its annual revenues .