We call it working a pendulum. As the attack shifts from side to side of the pitch, so must a team’s last line of defence. There have to be two players back at all times.

You do not want the opposition to kick to the corners, so there always needs to be the fullback and one of the wings covering the touchlines. The key to it all is communication. When the attack shifts direction, the defensive fullback has to be talking, telling one wing to push up and the other wing to drop back.

But you all need to be talking. One wing will be moving up and telling me to move across into his space. Constant communication is a massive part of a team’s success. The back five players are always talking in soccer and it is the same for a rugby team’s rearguard. It’s one of the most important parts of the game.

If you don’t get it right, the opposition will analyse the hole. Against England we knew there was a lot of space for Alex Goode to cover. He was covering one side of the pitch, but there was often a lot of room on the other side to kick into. Analysis and communication are a big part of the game.

But the players in front of you also have a big part to play in a successful back three. If the opposition bombs the ball back, then your teammates need to cover back down the chasers’ running lines. 9 and 7 are often the main players in that, but the centres will also often run their lines.

And you have to play what’s there on the day. Against England we realised the ref was not awarding any penalties against the team in possession for holding on. So the back three could hang on to the ball until the cover got to them, but our back row abandoned the jackal – there was no point – and took space instead.

A fullback is also often well placed to see the options ahead of him in attack. When Wales scored their second try against England, I saw they were short on numbers and called for a quick shift. Jamie Roberts did superbly to hit the line outside me and Justin Tipuric provided the final link.

In attack it’s all about numbers and keeping your head up. But then keeping your head up is a huge part of the full-back’s game. You have to see what’s in front of you and you have to talk.

Look out for Leigh’s content coming to the site soon