For that to happen a lot of equipment would have to be upgraded throughout ITN - don't forget even ITV News isn't HD yet. It took ITN until 2007 just to upgrade to widescreen so don't hold your breath!!
Yes, there's little point in making a studio HD if they're not acquiring and editing in HD.
News doesn't really benefit greatly from HD at the moment. Pre-planned features packages can look great in the format but for day to day newsgathering it's still easier to do things in SD especially if you're sending stuff back from abroad. Plus the move these days is for internet/IP based systems replacing video feeds on satellite - a live image via a 'videophone' or BGAN type system is barely SD let alone HD!
AP the news agency are going HD over the next 6 months, however how much of their footage will actually originate in HD I don't know