Ugandan academic, writer and feminist activist Stella Nyanzi has won the Oxfam Novib/PEN International Award for Freedom of Expression 2020.

Ms Nyanzi is a controversial academic, who campaigns on a variety of issues, from sanitary pads for schoolgirls to gay rights.

In a conservative society, where homosexual acts are outlawed, Ms Nyanzi is a divisive figure.

She was sentenced to 18 years in prison in August last year for "cyber harassment" after she published a poem on Facebook criticising President Yoweri Museveni.

She said she wished Mr Museveni, 74, had been burned up by the "acidic pus" in his late mother's birth canal.

"Stella Nyanzi has been deemed a criminal by the Ugandan authorities because she has criticised those at the highest echelons of power; though her words might be colourful and shocking to some", Jennifer Clement, PEN International president said in a statement released on Friday.

"At PEN we believe unshakeably in the need for writers to be able to criticise, parody, and mock at the highest levels. This award recognises the work she has done for women, civil society, and in the defence of free expression."