Marc Belli, Pennaeth Ysgol Uwchradd Mary Immaculate ers 2010 a welodd nifer o welliannau’n digwydd yn gyflym o fewn yr ysgol.  Ym mis Ionawr 2012, ymunodd Marc â’r Bwrdd Gweithredol Interim cyntaf yng Nghymru yn Ysgol Gynradd St Alban’s, wedi iddi gael ei rhoi o dan “fesurau arbennig” gan Estyn.  Mae Marc wedi’i hyfforddi fel Arolygydd Cymheiriaid Estyn, ac mae’n aelod o Banel Ymarferwyr Ysgolion Llywodraeth Cymru.
Marc Belli, Headteacher of Mary Immaculate High School since 2010 which has seen rapid improvements in the school.  In January 2012, Marc joined the first Interim Executive Board in Wales at St Alban’s Primary School after it was placed in “special measures” by Estyn. Marc is a trained Estyn Peer Inspector and is a member of the Welsh Government’s School Practitioners Panel.