Originally Posted by
Levelmind
Because to me it seems like, if they want you to use full length, ATC should specifiy it (?) and by saying "taxi holding point ..
From CAP 413, the UK R/T guide:
"Taxi instructions issued by a controller will always contain a clearance limit, which is the point at which the aircraft must stop, unless further permission to proceed is given. For departing aircraft, the clearance limit will normally be the holding point of the runway in use, but it may be any other position on the aerodrome depending on the prevailing traffic."
The default is the holding point for full length but if in doubt we would ask. Generally it is either down to the crew to request an intersection or ATC might ask if an intersection is suitable for traffic reasons. At many busy airports you won't get a straightforward taxi clearance all the way to the runway holding point anyway, it will be a progressive clearance via intermediate points.