that defeats the purpose of fog lights and highway code is very clear that you can use foglights with or without dipped beams (the former doesnt quite make sense except on older cars with crappy headlights though)
These are taken directly off the UK Highway Code website. Note 226 - must use headlights - may use foglights. Car manufacturers have to follow strict guidelines to allow the sale of new vehicles consequently one of those is that foglights are NOT enabled unless dipped beam headlights are switched on. There’s nothing wrong with dipped beam in fog, many cars I have owned over the years haven’t even had front fogs at all, even those that do have I very rarely switch them on, they make very little difference apart from keep a low flat beam of light designed to be below the level of water vapour (ie. Fog). The reason main beam doesn work is it’s a high beam that reflects back off the water vapour. The best foglights are square or rectangular not round as the reflectors keep the beam of light flatter.
BTW. I’m an ex automotive electrical prototype systems engineer
Rule 226
You MUST use headlights when visibility is seriously reduced, generally when you cannot see for more than 100 metres (328 feet). You may also use front or rear fog lights but you MUST switch them off when visibility improves (see Rule 236).Rule 236
You MUST NOT use front or rear fog lights unless visibility is seriously reduced (see Rule 226) as they dazzle other road users and can obscure your brake lights. You MUST switch them off when visibility improves.Edit….no idea why the text has gone bold above, can’t change it now & it wasn’t bold pre posting