Truth Begins lyrics

this is a brilliant, heart-wrenchingly beautiful song; Carl has a real way with words and it shows! I only wish I were as talented, and with such kickass melodies under my belt as well.
In my opinion, his referral to the listener as kid signifies the relationship, or at least Carl's initial impression of Pete as a 'little pipsqueak' (despite his only being but a year younger than the former). "So sow it up kid, have some clout" is encouraging his companion to 'toughen up, deal with this situation thoroughly.' (i.e Peter's addiction.)
"beg, steal and borrow" alludes to Peter's song, written for Babyshambles, and there are also other numerous references to the early days of the Libertines when Pete and Carl's friendship was firmly cemented. During this period of time, they would frequently get drunk or high together in the Albion Rooms (a filthy hovel that looms large in Libertine legend, in which they both used to reside) or elsewhere, and "fuck about".
"Truth begins" seems to equate to the importance of both parties (Carlos and Peter) facing up to the consequences of their actions, and therefore the real reason for the implosion of the Libertines a few years back, as well as the duo's relationship and their way of viewing one another; they cannot make excuses anymore- this is the real deal, a real confrontation.
What's more, before the conclusion of the song, Carl appears to be hauntingly insinuating that he is partly responsible for Peter's current state, or so it seems, with the sorrowful, guilt-ridden line "I may have hurt your mind". This implies that as Pete's elder, Carl feels responsible for guiding him correctly, as one might a younger brother. However, owing to Pete's addiction, he therefore feels his role in the former's guidance was a badly played one on his behalf, and the shame weighs upon him heavily as he is reminded of it in the tabloids, etc.