The company had sought a restriction order preventing publication of information contained in certain reports, but inquiry chairman Lord Hardie ruled that there was a “strong public interest” in their full release – a decision upheld by Lord Tyre in the Court of Session in May.

The company appealed the decision, claiming its documents should remain secret as they were commercially sensitive and could help competitors.

Now the Lord President, Lord Carloway has ruled the documents do not contain sensitive information, upholding the Lord Ordinary’s decision.

Edinburgh’s tram system was meant to cost £375 million and run to 15 miles by 2011. However, when it finally opened in 2014, the route was only nine miles long and had cost a staggering £776m.

The final bill is expected to be in the region of £1 billion.

Delays, budget overruns, contract oversight and other issues all fall within the remit of the inquiry.