The Public Inquiry into the troubled history of the project to restore trams to Edinburgh has concluded that the seriously delayed and much-reduced result, at a cost which was much greater than expected, was due to a ‘litany of avoidable failures’.

The original scheme had featured three tram lines, but when trams eventually started running in 2014, five years late, they served a 14km route which was only part of Line 1. The tram fleet was much larger than necessary because it had been ordered with the full network in mind and attempts were made to lease the surplus vehicles to other tram operators, including Transport for London, but without success.

The first line from Edinburgh Airport to the city centre via Haymarket was extended from the temporary city centre terminus to Newhaven in June, but a large proportion of the network remains on the drawing board.

The inquiry has been chaired by Lord Hardie and was set up nine years ago. The process has cost more than £13 million, and involved the examination of more than three million documents. The inquiry report runs to 961 pages.

The main conclusion is that Edinburgh City Council must take some of the responsibility, along with its development company TIE (originally Transport Initiatives Edinburgh), which the report says failed to collaborate effectively with the council and the tramway contractors, who became increasingly impatient.

The final report was accompanied by a video message from Lord Hardie, in which he says: ‘TIE's failures were the principal cause of the failure to deliver the project on time and within budget,’ but adds that the council ‘must also share principal responsibility with TIE for the delays in design’.

He also says the Scottish Government ‘recognised their mistake in withdrawing the oversight of Transport Scotland officials designed to protect the public purse’.

Lord Hardie has made 24 recommendations, including considering whether new laws are needed to provide civil and criminal action against people or companies who knowingly submit reports including false statements to councillors.

Other recommendations include that Scottish Ministers should undertake a review of public inquiries to determine the most cost-effective method of avoiding delay, in the interests of protecting the public purse and maximising the benefits from public expenditure on major projects, that Scottish Ministers should contemplate establishing a joint working group consisting of officials in Transport Scotland and representatives of the Convention of Scottish Local Authorities, and that the procurement strategy for any future light rail project should make adequate provision for the uncertainties concerning the location of utilities and redundant equipment.

He continued: ‘What is clear from the inquiry’s work is that there was a litany of avoidable failures on the parts of several parties whose role it was to ensure that public funding was spent effectively and to the benefit of Scotland’s taxpayers, and that the Edinburgh Trams Project was delivered efficiently.

‘Poor management and abdication of responsibility on a large scale have had a significant and lasting impact on the lives and livelihoods of Edinburgh residents, and the reputation of the city.’

Scottish Conservative MSP for the Lothians Miles Briggs said: ‘Lord Hardie is highly critical of councillors and the arms-length bodies responsible for the project, but he also singles out Scottish government for criticism. He is clear that ministers failed to protect the public purse and acted in the SNP's political interests, rather than the public interest.’

Cabinet secretary for transport Mairi McAllan said the Scottish Government would take time to consider the report, but he added: ‘The inquiry took too long, was too costly and in some instances the evidence heard does not support the conclusion drawn.’

When the 4.7km extension to Leith and Newhaven carried its first passengers in June, councillors said it had opened on time and within budget.