It doesn't have to be a declared war but it does have to be 'in the face of the enemy'. Recently in afgan a para cpl was awarded the VC (pos) for storming a taliban MG postion. Another guy was killed when he rescued his section from a minefield and was killed in the process. He was awarded the GC (pos). Whilst by all accounts he displayed the utmost bravary worthy of a VC in his actions, as his act was not 'in the face of the enemy' and therefore didn't meet the criteria for the VC. I think there have been a few similar incidents in Iraq in the last few years.