Tim Streater gurgled happily, sounding much
like they were saying:

If I'm stooging along the motorway at 65, look in the mirror, and
decide to overtake as the klod behind is a long way off, my
expectation is that he will still be a long way behind after I've
moved to the fast lane. I don't expect to find him up my exhaust
because the **** was doing 110.

If you're "looking", but not for long enough to gauge their rate of
approach, then you're not looking properly.

There is that, but if their rate of approach is low you may have to
look for too long.

Umm, you'd be able to tell their rate of approach was slow enough not
to be an issue, wouldn't you...?

Normally yes, but if the clown is going really fast then he may not be
that visible when you look.

If your eyesight is so poor that you are unable to see somebody closing
at a difference of 45mph (20 metres per second), then I wonder how you
cope with pulling out of a side junction onto an NSL road?

And then I'd rather focus on the lorry I'm overtaking, thanks.

Your hazard perception priorities are wrong. The truck is a far more
predictable, and therefore lower, risk.