Video review quietly made the high line safer to play

Tight offside calls used to be a gamble on an assistant's eyesight, and removing that gamble changed how far up defences dare to stand.

Before review, playing a high line meant trusting a man running sideways along a touchline to judge a two yard question at the exact instant a pass left a boot. He got most of them right. He also got enough of them wrong, in both directions, that a defence which lived on the offside line was accepting a real rate of goals conceded for reasons that had nothing to do with defending.

Take that error rate away and the calculation changes. A marginal call is now decided, slowly and unpleasantly and with a lot of lines drawn on a screen, but decided correctly by the standard the rules set. If your line is genuinely a yard ahead of the runner, you keep the yard. You are no longer paying an insurance premium against being wrongly overruled.

I would argue this is one of the most significant tactical consequences of the review era and it gets discussed the least, because the debate about tight offsides has been captured entirely by the question of whether the calls feel fair. Fairness is a separate argument. The tactical point stands whatever you think about armpits and toes. Defending high became a more reliable strategy, so more teams do it, so more matches are played in a compressed forty yard strip.

There is a cost the same change imposed, and it is worth being honest about. Assistants now delay the flag until a phase completes, which means a defence that has correctly played an attacker offside must still defend a shot at goal before the whistle comes. Goalkeepers hate it. It is also how you get a keeper injured making a save that never mattered.

And the deep block gained nothing from any of this, which may be why the gap between the high pressing sides and the rest looks wider than the money alone explains.

If the sport ever adopts a genuine daylight tolerance, where the attacker must be clearly ahead rather than measurably ahead, the whole calculation reverses within a season.

Defenders would drop five yards immediately, and half the tactical writing of the last decade would need rewriting.