Line of Duty viewers in disbelief over DS Steve Arnott last night

DS Steve Arnott must be secretly either Iron Man, or a cat (or, indeed, the Son of God) – how else could he have survived being belted by a baseball bat and thrown down three flights of stairs?

That’s what Line of Duty viewers are pondering after last night’s head-scratching fourth episode.

There was a collective cry across the land last Sunday as – at the close of the third episode – balaclava man sprang from nowhere to launch a brutal assault on the cop.

No one really dared believe that he could have survived such a vicious going-over – not least as blood was pouring from his head wound.

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But survive he did – for now, at least.

His injuries are numerous, of course: fractured skull, fractured vertebrae, broken pelvis, leg and ribs…

But, still, fans aren’t buying it as possible.

One viewer, stunned by his survival, echoed our thoughts on Twitter, commenting: “Steve Arnott must be made of steel.”

Others accused it of being unrealistic, with one writing: “I’ve believed every twist in every series of #LineOfDuty so far but Steve surviving a three-storey fall is TOO MUCH.”

Another disgruntled fan posted: “Steve thrown down stairs on the brink of death now sat up giving a statement, how pathetic.”

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Some viewers attributed it to divine intervention and declared it an Easter miracle!

One quipped: “Thank god it’s Easter. Steve just did a Jesus and rose from the dead.”

Another said: “Steve Arnott is Jesus!!!!!”

A third wit joked: “Great that on Easter Sunday, Steve is Risen.”

As fans of Line of Duty know only too well, though, there can be a huge plot twist at any time, so it’s anyone’s guess what the future holds for the AC-12 warrior…

For now. though, we’ve renamed him Steve Hardnutt.