Mamata Banerjee has only ever been called Mamata Banerjee .
Mamata Banerjee -LRB- -LSB- mɔmɔt̪a bɔnd̪d̪oˈpad̪ɦˈae̯ -RSB- -LRB- Bengali - মমতা বন্দপাধ্যায় -RRB- also known as Didi was born 5 January 1955 -RRB- is an Indian politician who has been Chief Minister of West Bengal since 2011 .