Jack McConnell (left) focussed on energy policy

Party leader Jack McConnell said Labour's commitment to supporting renewable energy would secure the industry's long-term success.

Elsewhere, the Liberal Democrats are pledging to recruit more nurses for the NHS, with the incentive of paying off student loans for those who find jobs in Scotland after qualifying.

The Tories have been focusing on crime, promising to put more bobbies on the beat with a zero tolerance approach to policing.

Greater investment

Speaking as he toured the Kvaerner oilfield plant in Aberdeen, Mr McConnell said Labour had the policies in place to ensure Aberdeen and the north-east retained its position as a world-leader.

He said the chancellor's decision to scrap petroleum revenue tax would encourage greater investment in North Sea oil.

The Labour leader also said his party's commitment to extending modern apprenticeships and supporting renewable energy would secure the industry's long-term success.

He said: "With an estimated 30 years of oil extraction left, Labour is acting now to guarantee Aberdeen's future.

The Lib Dems want to recruit more nurses

"So, even when the last drop of North Sea oil has been extracted, Aberdeen's position as the energy industry capital of Europe will remain."

The Lib Dems pledged to recruit 2,000 more NHS nurses to reverse Scotland's record as the sick man of Europe.

Spokesman Nicol Stephen said he wanted to pay off the student debts of new nurses and coax back those who had quit the profession.

He said his party also wanted to employ 300 extra hospital consultants and recruit 1,500 other staff, such as radiographers and dieticians.

Persuaded to stay

Mr Stephen, a deputy education minister in the last Scottish Executive, said the pledge of 2,000 more nurses was "over and above existing plans".

He said the figure was included in the overall target of 12,000 nurses - the number he said was needed over the next four years to replace those leaving and to increase the total.

He explained that the 2,000 would be provided at a rate of 500 a year with 100 coming from qualified nurses returning and the rest from new nurses persuaded to stay on by the scheme to pay off student loans.

The Tories vow to get tough on crime

He said the loan pay-off scheme was needed because 24% of student nurses dropped out of their courses with 76% of those citing debt as the chief reason.

Meanwhile, the Tories accused Labour of being "two-faced" over plans to end automatic early release for short-term prisoners, serving sentences under four years.

Leader David McLetchie said Jack McConnell had been given the chance to back Tory proposals to introduce those measures two months ago and failed to do so.

Vowing to get "serious on crime", Mr McLetchie said: "Mr McConnell is two-faced.

"Either he didn't believe in honesty in sentencing in February and he does now or he doesn't believe in it at all and is deliberately misleading the voters."

Green power

The Greens have been setting out their vision for a Scotland powered by renewable energy as an alternative to fossil fuels and nuclear power.

They claim that 90% of the energy used in Scotland at the moment comes from polluting energy sources like coal, oil, gas and nuclear power.

Scottish Socialist leader Tommy Sheridan promised to tear up every private contract in the NHS and return all staff to the public sector.

He told a union conference that health service workers would also be awarded a minimum wage of �7.32 and a maximum 35-hour week.

Mr Sheridan said: "Last year MSPs voted themselves a 13% pay rise to �48,000. If that's good enough for them, it's good enough for health workers who do far more valuable jobs than MSPs."