The pair are ever-present in 29 Barclays Premiership games so far and a key reason why we've kept 15 clean sheets in all competitions this season, 13 in league action.
Both are back in the England squad for the World Cup qualifiers against Northern Ireland on Saturday and Azerbaijan on Wednesday and both face a battle to start - Robbo is winning his against David James at the moment, starting the last five internationals, but Ledley faces tough opposition from the likes of Rio Ferdinand, Sol Campbell and John Terry.
"Ledley's done really well this season and has gone from strength to strength," said Robbo. "He's a class act and has played well week in, week out.
"But we can all see the competition for centre-back places for England.
"Look at the squad and there are four top-class centre-halves in Ledley, Sol Campbell, Rio Ferdinand and John Terry.
"Picking two to play from that is almost unfair on the other two. It's a great position to be in for England but I suppose it's unfortunate for Ledley, I'm sure he'll win plenty of caps in his career though."
Paul Robinson has seen more than most of Ledley King this season and believes the skipper is getting better and better.