Soldato
Even if it is red for an hour, you can't cross it. The rule is absolute. There could be a reason why it is red for all you know.
Opening it up to judgement is a slippery slope the law avoids.
The same rule (assuming you are referring to rule 176) also states: "If the traffic lights are not working, treat the situation as you would an unmarked junction and proceed with great care."
It's somewhat ambiguous what "not working" means, but I reckon you would have a good argument in court that a light stuck on red for hour would be reasonable cause to believe it was "not working".