SCOTLAND will become dependent on energy imported from England unless it can move away from "emotional and politically motivated" rows over wind farms, nuclear power and fracking, one of the country's leading engineers has warned.

Professor Gary Pender, head of the Institute of Civil Engineers in Scotland, called for a national debate on the country's long-term energy supply.

In one of the starkest warnings yet about future energy security, he said Scotland's historic position as a net exporter of electricity would be reversed without major new developments.

He conceded that wind, nuclear and the potential new power source of unconventionally extracted gas were controversial but added: "We need to move beyond this at times irrational and ill-informed discourse about all these forms of energy generation, and conduct a thorough, expert-informed assessment of the right approach for Scotland."

Mr Pender was speaking ahead of a report by ICE Scotland, to be published next month, which highlights the country's energy "quadrilemma" - the need to cut carbon emissions, minimise consumer costs and ensure secure supplies while satisfying public opinion.

Of five infrastructure areas examined by the report, Scotland's energy policy caused the greatest concern.

Wind power has produced an increasing share of Scotland's energy needs in recent years but a number of major nuclear and fossil fuel generators, which produce "baseload" power are about to close.

Longannet, in Fife, one Europe's biggest coal fired power stations, will close next March.

Scotland's two nuclear plants, Torness, in East Lothian, and Hunterston B, in Ayrshire, will only remain operational until 2023.

Between them, the three facilities account for half Scotland's generating capacity.

Mr Pender said: "Scotland will transition from being a net exporter to being a net importer of electricity if the closures of Longannet, Hunterston and Torness are not replaced by new development.

"We will be calling for a national debate on how we, as a country, deal with this to ensure that we have a resilient supply with sufficient capacity for the long term."

He added: "Energy policy is hugely politically controversial, with wind power, nuclear power and onshore gas extraction provoking particularly emotional and politically motivated responses.

"Energy is the part of Scotland’s infrastructure network which concerns us most, and we encourage the Scottish Government, working with the UK Government, to provide a clearly articulated vision for the future. Decisions must be made on evidence and resilience, not on emotion and politics."

SNP ministers have postponed a decision on whether to allow fracking until 2017 after coming under intense pressure from grassroots party members to ban the process.

The SNP Government has also heavily criticised the UK Government's decision to subsidise new nuclear powers stations in England, claiming the projects are too expensive and switch resources from renewables.

Scotland already has to import energy from England on days when wind turbines produced too little power to keep the lights on.

Scottish Conservative energy spokesman Murdo Fraser said: "This is a significant intervention from a well-respected expert industry group – and the SNP will have to listen.

"The Scottish Government is playing to the gallery by banning or slurring forms of energy it doesn’t think SNP members like.

"But instead of pandering to the green lobby, ministers have a responsibility to keep the lights on and make sure energy prices are low."

He added: "The SNP should swallow its pride, forget about impressing its new socialist members, and bring forward a balanced energy policy."

A Scottish Government spokesman said: “As we move to a low carbon energy system over the longer term, we expect Scotland to maintain its position as a net exporter of power even after Longannet closes, whereas the UK as a whole is increasingly reliant on imports from other European countries."