Whatever may or may not be the case with cross-border fighting, this more or less officially confirms what at least one British commander in Iraq stated publicly a year or two ago, than an undeclared war between Britain and Iran was underway. It would certainly be possible that British troops fighting weapons smugglers and IRGC Al-Quds Force troops along the border might find themselves in hot pursuits situations. I've also noticed that the Iranians have not attempted to capture British troops in recent months like they have done at a few times in the past.