A four-year struggle to restructure Delphi passes another milestone on Friday with competing bids due for the bankrupt Michigan-based company, one of the world's biggest car parts makers, writes Bernard Simon .

Delphi and General Motors, its former parent and biggest customer, have thrown their support behind a proposal from Platinum Equity, a California-based private equity firm. But providers of $3.3bn in debtor-in-possession loans have persuaded a bankruptcy court judge to open the process to other bidders.