World's Toughest Sudoku - Solved

Here's a solution to the 'World's Toughest Sudoku' puzzle that is doing the rounds of the news.

Not sure what the basis is for calling it the toughest sudoku puzzle but here is the solution.

Allow me to gloat over it :). Used my own excel sheet that I developed a little while ago. Took about an hour to solve it. Would be very tough to do it manually on a single sheet . The solution needs multiple iterations. Much easier to do conjectures using the computer as it's easy to rollback at any stage.