It says on this website that it's Feb some time, I would assume beginning or middle! As it's about 3 weeks after the US starts playing it.
See link below.
Sometime in February :)
The vampire diaries will be on ITV2
The CW in the US and ITV2 in the UK
Vampire Diaries season 3 in the UK is on ITV2 every Tuesdays at 9:00PM
In the UK, The Vampire Diaries is on the 15th October 2012 at 9:00pm. Channel: ITV2
ITV2 @ 9pm
october fifth on ITV2
it starts on 11th october 2011 on itv2!
The Vampire Diaries returns on Tuesday 1st Febraury, ITV2 9pm
october 5th in the UK on ITV2
october fifth on ITV2 ^_^
august311896 11th October, it says on the facebook page: The Vampire Diaries - ITV2 :D