Simpson is up and doing his best to survive but Williamson is relentless.

Simpson is in a world of trouble as he goes down again.

Simpson is sent to the canvas after a massive left from Williamson.

Can he end it now?

Josh Warrington speaking to BBC Sport at ringside: "It certainly suits the Leeds Arena! Callum is letting that jab go a little bit lazy and Troy is coming over with the big punches. He looks like he has been hurt a fair few times. When he sticks to his boxing, he will look a lot sharper."

It is hard to score but Williamson is well in charge now.

Simpson needs to rally and rally very fast.

Both come in close and Williamson lands a punishing short left hook. He springs forward once again to land a lovely left and right.

Williamson makes Simpson miss and picks his punches nicely on the ropes. He's bullying Simpson now.

A clear round for Williamson as he raises his hand at the bell.

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Simpson keeps shaking his arms out. Releasing lactic acid or an injury?

Stacey Copeland
Retired boxer on BBC Radio 5 Live

Williamson certainly seems to have quietened this crowd down because it was raucous when Simpson entered.

There is that little sense of is their man getting the job done? Williamson has been on the front foot and pushing Simpson back.

Perhaps Simpson has work to do here.

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Williamson's right hand can't miss tonight but Simpson takes it well before unloading to the body. You do get the feeling Simpson's power isn't bothering Williamson, though.

Williamson is getting the better of this one now as he lands hard twice.

I have Williamson on my scorecard after eight rounds.

This Yorkshire crowd isn't quite as raucous. They know their man Simpson is in a real battle here.

Simpson is looking to counter Williamson when on the ropes but instead lands with a nice double jab. He needs to keep that distance if he's going to take the rounds here.

Williamson uses his experience to tie Simpson up and stop him from working. Both engage once again and Simpson connects with a hard right hook but Williamson lands too.

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This is so hard to score, by the way.

Do the judges prefer the work rate of Simpson or the better punches of Williamson?

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Simpson looks for more distance to box at range as Williamson looks to time the best moment to jump in with the overhand right. Williamson is very crouched, making it hard to predict what punch he's going to throw next.

Williamson lands a solid left hook in the final seconds of the round as we reach the half way point.

Stacey Copeland
Retired boxer on BBC Radio 5 Live

We expected this to be really physical and it has delivered so far.

It is high quality as well though, not just about the aggression. They are both quality fighters and we are seeing their full skill set here.

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Simpson looks to get going on the inside but isn't able to find the room as Williamson can connect with another overhand right before Simpson unloads on the ropes.

We know he doesn't possess that one-punch KO power so flurries of hard punches like those are massive.

Stacey Copeland
Retired boxer on BBC Radio 5 Live

Williamson is constantly trying to change the levels or the height, trying to spring off that back foot with an overhand right.

Perhaps he needs a bit more variety now as Simpson seems to have been preventing that.

A little bit of frustration is building here now.

Simpson looks to come with the hooks but Williamson catches him on the way in with a short left hook before being hit hard with a stunning left again.

The referee calls him to give Williamson a ticking off for shoving the bottom of his gloves into the face of Simpson.

A bit of a messier round that one.

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Stacey Copeland
Retired boxer on BBC Radio 5 Live

Simpson doesn't tend to possess that one-punch devastating knockout power, but he can overwhelm and put you under pressure and that is what he has done in spells.

Williamson is adapting well though and is finding gaps of his own.

Kell Brook spoke to BBC Sport at ringside: "It's warming up very nicely. Callum needs to keep it long. Troy is getting in and letting that hand go and he's made Callum very aware that he needs to be sharper.

"We're seeing fireworks tonight; it is a clash of styles and it is warming up very nicely."

It's been a great watch so far and hard to score!

I've got it 2-1 Simpson through three.

Simpson works well at range early in the round - firing spiteful shots in and landing. Williamson springs and connects with the straight right but Simpson comes back with a left hook and uppercut before they engage on the ropes.

Neither fighter is giving an inch here. It's being fought in the centre ring and both are looking to land big.

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