A LEADING oil exploration expert has predicted a second major oil boom for Scotland as the country's future energy reserves dominated the run-up to tonight's second televised referendum debate.

Professor John Howell of Aberdeen University, an expert on geology, has forecast huge potential for development west of Shetland.

The professor of petroleum geology and Yes campaign supporter argues that, while there are no certainties in oil exploration, a second oil boom is possible.

He said: "The geology west of ­Shetland may be challenging and fraught with uncertainty but I for one would never underestimate the ingenuity of the explorers and I certainly will not be surprised if major discoveries are made there in the next few years, totally changing the perception of the region and opening up a second major oil boom for Scotland."

He points out that, while the UK Government pursues fracking against much public opposition, companies such as Total and BP are investing in the likelihood of more finds west of Shetland. "They clearly see potential in the region," he argues.

"All areas were once frontiers, at the limit of what the engineers could manage and what the geologists could understand. In the 1960s a senior BP geologist famously offered to drink all the oil found in the North Sea, so sure was he that the area was barren."

His comments came ahead of tonight's second TV debate between First Minister Alex Salmond and the Better Together leader Alistair Darling. Mr Darling was seen to have won the first debate, but Mr Salmond is expected to hit back, with bookmakers again placing him as the likely winner of the BBC event at Kelvingrove Museum in Glasgow.

Oil is expected to feature heavily in the debate following last week's intervention by industry leader Sir Ian Wood, who downgraded his prediction of the amount of oil left off Scotland from 24 billion barrels to 16 billion.

Other topics expected to feature are currency, Europe and the NHS.

The debate will be streamed live on HeraldScotland as part of a comprehensive package of reporting, reaction and comment. Join us here from 8.30pm to give your views via our readers' forum.

A statement issued at the weekend by Oil & Gas UK, which describes itself as the voice of the offshore industry, said: "We note Sir Ian Wood's view that between 15 and 16.5 billion barrels of oil and gas may be produced from the UKCS (UK Continental Shelf).

"Oil & Gas UK, however, believes there is a broader range of possible outcomes and we remain of the view that there could be up to 24bn barrels of oil and gas to recover."The statement added: "In order to achieve the optimum result, whatever the outcome of the referendum, it is essential that both governments must work with industry and each other to maximise economic recovery of our indigenous offshore oil and gas resource."

Energy Minister Fergus Ewing said Professor Howell's comments were "encouraging, showing our huge potential".

He also welcomed comments from Alex Russell, Professor of Petroleum Accounting, and Peter Strachan, Professor of Energy Policy, both of Robert Gordon University, that the Office of Budget Responsibility's oil forecasts were "ludicrously pessimistic".

They also agreed with Professor Alex Kemp, one of the world's leading oil economists, who has carried out advanced modelling on North Sea oil and gas fields. He said: "The ultimate potential of 24 billion barrels of oil equivalent foreseen by Oil & Gas UK appears plausible."

The Chief Secretary to the Treasury, Danny Alexander, insisted the Scottish Government's continued overe­stimation of reserves compared to last week's projection by Sir Ian Wood meant that by the proposed time of independence in 2016 the country's deficit would rise further, to £700 higher per head than the rest of the UK.

"It undermines the case that the SNP has made, which is built on fantastical over-optimistic oil predictions in order to pretend that so­mehow in an independent Scotland various policies could be afforded," Mr Alexander said.

"An independent Scotland from day one would have no choice but to make substantial cuts to public services or substantial increases to income tax."

Kenny Anderson, Leader of Business for Scotland in Aberdeen, said: "We have stated that 24 billion barrels of oil is a reasonable target."

He cited sources including Oil & Gas UK, Professor Alex Kemp, Sir Donald McKay and many other leading forecasters in addition to Sir Ian Wood himself.