Born in the eastern Ukrainian city of Dnipropetrovsk, Tymoshenko earned an economics degree and began her career as a financial manager at a machine-building factory in the Soviet era.

The ''gas princess'' nickname dates from when she and her husband, Olexandr, 47, ran a fuel company that eventually became United Energy Systems, the country's top gas dealer in the mid-1990s.

Photograph: Getty Images 

Critics accuse Tymoshenko of illegally pocketing huge profits from her United Energy System deals and of evading taxes - suspicions that led to her brief imprisonment.

Tymoshenko denies all the accusations, saying her company in fact helped energy and cash-starved Ukraine survive in those chaotic years.