The researchers took into account periods of drought and World War II, because of their economic and psychological impact.

Suicide rates were higher during periods of drought and lower during WWII.

But after adjusting for these factors, the figures clearly showed the highest rates of suicide occurred when both Conservative state and federal governments were in power.

Conversely, the lowest rates occurred when state and federal governments were both Labour.

Middle aged and older people were most at risk.

When the Conservatives ruled both state and federal governments, men were 17% more likely to commit suicide than when Labour was in power. Women were 40% more likely to kill themselves.

Conservative rule traditionally implies a less interventionist and more market-orientated policy than Labour rule