Bill Gates has finally got a degree from his alma mater Harvard, 33 years after he dropped out to start Microsoft. 

Gates used his acceptance speech to call for greater steps to tackle global inequality, describing as "revolting" the fact that children in the developing world are dying for want of medicine costing less than $1.

"I left Harvard with no real awareness of the awful inequities in the world: the appalling disparities of health, wealth and opportunity that condemn millions of people to lives of despair.

"I learned a lot here at Harvard about new ideas in economics and politics, and I got great exposure to the advances being made in the sciences.

"But humanity's greatest advances are not in its discoveries, but in how those discoveries are applied to reduce inequity.

"Whether through democracy, strong public education, quality healthcare or broad economic opportunity, reducing inequity is the highest human achievement. "

Gates urged his audience to become activists and take up the fight to save those less fortunate than themselves. He declared that he would be devoting all his energies and resources to the project once he had eased himself out of Microsoft next year.

On a lighter note Gates thanked the university for his Doctor of Law degree, saying that it would make his father, who was in the audience, proud, and could come in useful.

"I have been waiting more than 30 years to say this: 'Dad, I always told you I'd come back and get my degree,'" he joked.

"I want to thank Harvard for this timely honour. I will be changing my job next year and it will be nice to finally have a college degree on my resume."