The official investigation into the Edinburgh tram project is set to exceed £13 million, it has been revealed.

The latest financial figures showed the inquiry will cost the public purse £13,100,812 by the end of this financial year.

The vast majority will be spent on staff costs, which are due to reach £6,100,262, while legal fees are projected to hit £3,076,224 – a combined total of £9.1m.

A further £1,384,121 is expected to have been spent on IT system costs, as well as £868,859 on rent for office facilities and £419,928 on the inquiry’s media team.

The costs were revealed following a Freedom of Information Request to Transport Scotland from the i newspaper.

The inquiry, chaired by Lord Hardie, is examining why the scheme went significantly over-budget and delivered years later than first planned.

The eventual cost of the project at £776 million was more than double the sum earmarked at the outset.

The inquiry was first set up in 2014 by then first minister Alex Salmond who reportedly said he wanted it to be “swift and thorough.”

However, more than eight years later, it has yet to produce its report.

A Transport Scotland spokesperson said: “We have agreed to continue to fund the costs of the Edinburgh Tram Inquiry until it is completed, final costs will be published when they become available.

“Staffing matters, including how many people the inquiry employs and how much they are paid, are a matter for the inquiry. This is because, as a statutory inquiry, it is independent of Scottish Government.

“The Edinburgh Tram Inquiry was, of course, established to look at how any mistakes or failures could be avoided in future major tram and light rail infrastructure projects and we look forward to receiving Lord Hardie’s findings when they are made available.”