It appears to me that light is actually not slower. Instead of taking the straight line, it is just taking a longer route, hence arriving little late.

"it may also be possible to speed it up by around one femtosecond faster than the speed of light in a vacuum"
WHAT?! how could you include this and not elaborate at all???
I say the quoted passage is complete rubbish because nothing can go faster than the speed of light in a vacuum. but it's such a large claim, I want more information

Once again, a science article gets it wrong. The limit to the speed of light is an UPPER limit. Nothing can go faster than "the speed of light in a vacuum". It has always been known that it can indeed go SLOWER. So this article claiming that there's something NEW about the speed of light is just dumb.

Lightspeed is NOT a constant! This was proven by Hubble only a few years after Einstein's erroneous assumption. It is a shame that this fact is ignored even by today's most famous scientists.

This might be trivial but given the information in the article the speed of the light is not slower but rather the distance traveled is greater. The speed of the twisted light is likely the same speed as the non-twisted light, the difference is that it did not travel the shorter direct path from A-B. "According to the team, the ability to slow down light by altering its structure implies that it may also be possible to speed it up by around one femtosecond faster than the speed of light in a vacuum." this claim is false, again using only the information in the article, the twisted light is traveling further but at the same speed as the non twisted light. Unless they figured out how to shorten the distance from A-B (and if they have then NASA is interested) the twisted light is not going to get from A-B faster than the non-twisted light. Or am I missing something here? I know Quantum theory is not my expertise and I may be thinking only in Newtonian physics.

The implications of this discovery (that light speed is not a constant) go much further than communications theory. This could change the entire notion of the nature of the universe.
Hubble used the red shift apparent in astronomical observations to prove the universe is expanding. The underlying theory is that the speed of light is a universal constant and therefore the only possible explanation for red shift is an expanding universe. I have always hated that logic since we have never been able to observe any of this stuff from anywhere other than our home on Earth to verify the theory. Now that it seems there are ways to slow down light in a vacuum it might be time to reexamine the notion that the universe is expanding. The existing conclusion is flawed by the realization that the speed of light isn't constant.

Your interpretation seems to be correct, Paul Anthony - at least based on the information provided within the article.
I think I'll try looking more into the "tilting" that was described to get more information about it.

Could Einstein be wrong?

I may have the terms wrong but this is just showing the difference between the vector speed of the actual particles versus the gross speed of the "beam" composed of the particles. Non-spinning light has a vector of "straight ahead" and goes "straight ahead" at the speed of light. Spinning light has two vectors, the vector in the angular direction plus the vector in the "straight ahead" direction. The geometric sum of those two vectors should be the actual "speed of light" . Because the actual speed of light is a constant, the only way to have light "vectored" in two directions is for each of those vector speeds to be something less than the actual "speed of light" AS MEASURED in the direction of each vector. The combined vector speeds will be the actual expected speed of light as we think of it.

Well duh. If the photon is corkscrewing then of course it is not going to cover a given distance compared to a photon traveling in a strait line. The velocity of both remains the same.