During the Yugoslavian war there was a stand-off between the Russians and some American troops around the Pristina airfield.
"The following morning, Sunday 13 June, Clark arrived at Jackson's HQ in Skopje. It was pointed out to Clark that the Russians were isolated and could not be reinforced by air and that Russian support had been a vital part of getting a peace agreement; antagonising them would only be counterproductive. Clark refused to accept this and continued to order that the runway be blocked, claiming to be supported by the NATO Secretary-General.[2] Jackson refused to enforce Clark's orders, reportedly telling him "I'm not going to start the Third World War for you."[5] When again directly ordered to block the runway, Jackson suggested that British tanks and armoured cars would be more suitable, in the knowledge that this would almost certainly be vetoed by the British government. Clark agreed."
What you are suggesting here is that the British would start World War III of their own accord and that Nato would follow them if they did so.
Not a chance.