If it is found National Express failed to meet these terms, the options available are to either award to the contracts to losing bidder, and current operator DB Regio or restart the tendering process.

In February National Express Rail, the German subsidiary of British transport group National Express, was awarded two contracts to operate the Nuremberg S-Bahn network for 12 years from December 2018 using a fleet of new EMUs supplied by Škoda Transportation. DB Regio subsequently launched a legal challenge against the contract award.

The court has not ruled whether the financial guarantees offered were sufficient or not - but noted that they depended heavily on the revenues from National Express Rail's other German regional rail contract in North Rhine Westphalia, which begins in December.

A €30m "comfort letter" offered by the British parent company late in the process may not be considered sufficient, as the total value of the contract is around €1.4 billion over the twelve-year term (around €117m for the operation of 7.3 million train-km per year).

The court has decided to not to confirm whether or not these arrangements are adequate, leaving BEG to establish whether National Express has met the terms of the contract, which looks likely to invite an immediate further legal challenge from DB.