THE public inquiry into the shambolic £776 million Edinburgh Trams project may take up to two years to deliver its findings, it has emerged, despite the Scottish Government saying it would be held "quickly and efficiently".

The potential timescale was revealed at a recent meeting of the public spending watchdog Accounts Commission for Scotland, which has previously reported on problems with the trams.

The public inquiry into the Holyrood Parliament fiasco took 15 months from start to finish.

First announced in 2003 with a price tag of £375m, the Edinburgh Trams project was supposed to be operational by 2009.

However, after a five-year delay involving widespread traffic chaos and a bitter dispute with the main contractor, a severely shortened route of about 8.5 miles was finally opened in May this year.

David Mackay, who quit as chairman of TIE, the arms-length company in charge, in 2010, branded the project "hell on wheels".

At one point, work ground to a standstill because of a legal dispute between TIE and the main contractor, Bilfinger Berger.

In June, First Minister Alex Salmond - who like others in the SNP opposed the project - announced there would be a non-statutory inquiry led by Lord Hardie, the former judge and Lord Advocate.

The terms of reference are to inquire into the delivery of the project, to establish the cause of the delays and cost overruns, to examine the consequences of the various failures, and to make recommendations that could benefit future tram and light rail projects.

A key focus is expected to be the form of the contract between TIE and Bilfinger Berger and the reasons for the dispute over it.

Senior Scottish Government solicitor Gordon McNicoll has been named the solicitor to the inquiry, while former Treasury solicitor Jane Ferrier is the inquiry's assistant solicitor.

The inquiry has also secured premises at Waverley Gate at the east end of Princes Street in the capital, which may be used for hearings.

Salmond said he chose a non-statutory inquiry, which relies on witness co-operation rather than compelling evidence, so it could be conducted "quickly, efficiently and cost-effectively".

The timetable was never spelled out. However, the Accounts Commission board last month discussed a report on the trams inquiry which had been prepared following a meeting between ­McNicoll and Accounts Commission audit staff.

Discussing the meeting, Fraser McKinlay, director of p­erformance audit and best value at the Accounts Commission, said: "There is no timetable for when Lord Hardie might report his findings but, based on other public inquiries, this might take up to two years."

Two years would far exceed the inquiry into the country's biggest procurement fiasco before the trams - the Scottish Parliament project - which eventually ran ten times over budget and opened three years late.

In June 2003, then first minister Jack McConnell appointed Lord Fraser of Carmyllie to chair the inquiry and he reported in September 2004.

However, other recent inquiries have dragged on.

The inquiry into the outbreak of C difficile at the Vale of Leven hospital which claimed 28 lives has so far lasted five years. It was supposed to cost £4m and report in May 2011, but is yet to report findings and has cost £10m so far.

Labour transport spokesman Mark Griffin said: "Serious questions need to be asked about the time this inquiry will take.

"When previous large-scale inquiries have taken far less time, the question has to be asked, why the delay in reporting? We need answers as to what went wrong and we need them quickly."

A spokesman for the Edinburgh Trams Inquiry said: "There are a number of stages to the actual Inquiry, with each dependent on the previous.

"We are currently in the preliminary investigation stage, which includes retrieving and reviewing documents, scoping the work to be carried out and identifying potential witnesses, as well as securing sufficient staff and technical resources to manage the material.

"Only once this has been completed can a determination be made about when public hearings will be held. Lord Hardie will carry out the inquiry as efficiently as possible in a thorough manner, involving the examination of a large body of evidence."