a) Goes both ways, but lets say the lorry was doing 45 in a 50 zone with two lanes, rather than stay back you could accelerate and go round him, in doing so you hit 56mph with the intent to then drop to 50.
Or
b) Do you fall back to 40 and only regain back to 45mph matching the lorries speed in front with now some distance between you?
I know I'd do "A", have done so on many roads, its a big national sign on a country road and there's some tw@t doing 50 opposed to the 60, for me to get round, doing 60 would be dangerous as most country roads don't have much straightness, so I'd hit 70, get past and drop to 60mph... But thats my view
