The Isle of Man's former Chief Minister Donald Gelling has now officially begun his retirement, after a 45 year career in politics.His long stint in public life began in 1961 when he joined Santon Commissioners.On last night's Agenda programme, Mr Gelling reflected on the many challenges and changes he - and the Island - have faced.45 years ago the Island's population was 48,000 - now it stands at 80,000.David Callister asked him how much more it could grow.Mr Gelling pointed out the Island's population fluctuated from one extreme to another in the days of mass tourism. He suggested the current situation is in many ways more satisfactory: