[bilky asko]

Thing is that the BBC have a news channel, so can continue the coverage there. ITV don't and they know that people will turn to Sky or the BBC to find out what's going on when they get home if they're not covering it.

Incidently it's the same on radio, Radio 4 finished their 6 o clock news and went to Just a Minute. 5 Live continued the coverage

I think this is precisely the reason for ITV doing what it did. If ITV did something similar to what Brekkie suggested - a 1 minute newsflash prior to the regional news - they'd have lost viewers in swathes.