Men jailed after sniper rifle found in back of minicab in South Croydon (a .22 LR!)

[Straw Man]

84. Yeah, OK.

This kind of weapon can be used in relatively short distances to its target.

...

That's a snipers weapon.

A short-distance sniper's weapon is an oxymoron.

Police use .22 caliber rifles with suppressors for tactical duty so somebody up to no good could use them as well.

Police in this country certainly don't. The Israelis use them for hostage rescue and riot control in order to minimize collateral damage. This may be a corollary of their readiness and willingness to employ deadly force in many situations.

It's my understanding that a .22 cal round can leave a quarter-sized hole in a target. Picture that wound in somebody's head, and they're dead.

A .22 caliber solid round fired through a paper target makes a hole that is less than a quarter of inch in diameter: .22 inches, in fact. A hollowpoint will do the same, since the paper doesn't offer enough resistance to make the round expand. A harder target will make the round expand, but as it expands, it loses penetrating force. A .22 hollowpoint isn't likely to penetrate a human skull at anything but point-blank range.

What would you use a .22 caliber rifle with suppressor and hollow point ammo for?

I would use it for hunting small game. Some European countries require the use of suppressors for hunting, in order to avoid disturbing people and livestock.