Dylan Hartley is posing Lancaster's biggest selection headache to date, says Will Greenwood

Sky Sports' Will Greenwood says the selection of Dylan Hartley is Stuart Lancaster's biggest selection dilemma to date.

Lancaster is facing his toughest decision since he took over as coach of England. His best hooker has missed a year of rugby in total through suspension alone, and the RFU will have to decide whether or not his discipline is too much of a risk to warrant selection. With Hartley's latest suspension, he will have missed 54 weeks of rugby due to ill-discipline.

There have been recent selection issues that Lancaster has faced since taking over at Twickenham. The Armitage and Abendanon debate has long raged on, but in reality there was no big decision for Lancaster to make because he'd made the decision in the beginning to back the policy of not selecting overseas players.

So even though the two of them are playing good rugby, leaving them out wasn't a difficult choice because that decision had been made ahead of time.

Danny Care's indiscretions were a little more difficult to deal with, as were those of Delon Armitage, but the Dylan Hartley selection headache will weigh heavily on Lancaster and his team. I personally don't think Hartley is quite as good a ball carrier as Tom Youngs, but his concentrated ability in the lineout is currently rivalled by none in England.

If he was issued with a final warning at that time, then Stuart Lancaster is faced with an easy decision - Hartley must go.

Pressure

New Zealand won the World Cup in 2011 with a lineout that stood strong against all opposition. In the 2007 World Cup, South Africa stole seven lineout throws from England to win the final, and in 2003 it was a long-ranging throw from Steve Thompson to Lewis Moody that opened up the opportunity for Jonny Wilkinson to drop that goal.

If England needed to make that same throw under pressure today, there isn't anyone in England better qualified to do it than Dylan Hartley.

However, you have to look at where Hartley fits into the culture that England have cultivated as a squad. I don't know if Lancaster put Hartley on his final warning when he elbowed Matt Smith in Northampton’s game against Leicester last year. Hartley said at the time that he was on his last chance, but that doesn't mean it was an official ultimatum handed to him by Lancaster and the RFU - it could just have been what Hartley took away from a stern conversation.

If he was issued with a final warning at that time, then Lancaster is faced with an easy decision - Hartley must go. But if he didn't, then Lancaster will need to decide if his star hooker is worth the potential repercussions of his hot temper.

That is why this decision is such an important one, because rugby ability has nothing to do with it. You can argue the merits of Elliot Daly over Henry Slade in the midfield. You can argue the benefits of having Ed Slater in the second row instead of Dave Atwood. Those are options around which you make subjective decisions that will impact individual players and your game plan, but the decision about Hartley has the potential to impact the culture of the squad as a whole.

Standards

When I played for England, Clive Woodward would not include people in his team if he didn't trust them. The fundamental desire he had as a coach was to create a squad of players that bought into each other. We had the rules that were set to us by the RFU, but we had rules and standards that we set for ourselves as players.

And when you make your own rules, there's no doubt - if you break them, you're out. We knew that if we fell off that path, then our place in the squad was compromised.

But this isn’t Woodward’s England, it’s Lancaster’s - and that’s why it’s so difficult for any former player to say whether or not Hartley should be picked for the World Cup. From the outside, it's impossible to say what should be done because we aren't a part of the England squad and its culture.

We haven't been sitting in the meeting rooms when discussions have been taking place. We weren’t there when Lancaster last spoke to Hartley about his discipline issues, and we aren’t there at the moment for the current conversations.

Of all the sports in the world, rugby is one of the hardest to referee because of the sheer amount of context and interpretation that is required in order to make a decision. This week, Stuart Lancaster is finding out that’s exactly what makes coaching rugby difficult too.