The UK Government's financial watchdog does not have a full understanding of Scotland's economy, according to experts.

The Office for Budget Responsibility (OBR), established by the Tory-Liberal Democrat coalition to produce independent future economic forecasts, lacks sufficient data to produce "sophisticated" forecasts for Scotland, Holyrood's Finance Committee heard.

A Scottish version of the OBR is "highly desirable" now that Scotland is getting more devolved tax and borrowing powers and will be even more crucial if it becomes independent, according to Royal Society of Edinburgh fellow Jeremy Peat.

Glasgow University professor of macroeconomics Campbell Leith said a lot of work is required to allow the UK OBR, or any prospective Scottish fiscal body, to produce "solid" forecasts.

The Royal Society has noted concerns about whether UK OBR "fully captures the distinct circumstances and drivers in Scotland".

Prof Peat said: "It's evident that they don't necessarily have the full understanding of all the niceties of the issues that are around. Inevitably, if the work they do is at a UK level, the work they do at a Scottish level may be part of a narrower element of their remit and, therefore, they may not necessarily capture all that should be captured.

"There are two types of forecasters: those who don't know and those who don't know that they don't know; and it's the latter type who are always the most dangerous.

"You have to accept that there are uncertainties. No one should take any forecasts as gospel and assume they are correct."

An independent fiscal institution (IFI) for Scotland could work with the OBR to produce "more refined work on Scotland".

He said: "Setting up an IFI now for Scotland is highly desirable. At the moment, one should consider a somewhat narrower remit that fits the present devolved circumstances but be thinking through what would be required in the event of a Yes vote. At that stage, these issues of exactly how the full forecasting role would work would become wholly pertinent."

The OBR's forecasting for Scotland is "mechanistic", Prof Peat said.

"They claim that one reason for that approach is a lack of available data. There may well be other data coming on stream that will improve the sophistication of that forecast.

"The Scottish Government is also engaged in trying to improve their macro-modelling capabilities but these aren't quite on stream yet, so there is still quite a lot of capacity building to be done to build solid sophisticated forecasts."

Finance Secretary John Swinney announced plans for a Scottish OBR following a series of "inexplicable" projections by the UK OBR.

The body has been criticised by Scottish ministers for producing what they say are pessimistic forecasts for Scottish oil revenues, which have gone on to inform modelling for an independent Scotland by, among others, the Institute for Fiscal Studies.

Mr Swinney said a Scottish OBR is necessary to manage the new devolved fiscal powers in the Scotland Act, but his opponents have accused him of "cooking the books and looking to appoint his own chef".