Friends, I ran into a problem. This deficit has br...

I thought it was possibly early Leaf Septoria, the way you described it sounded like it spread, It occurs mainly in summer when high temperatures combined with rain or moisture from watering cause the leaves to become wet. Just the fact you live in the UK makes me think "moist". Calcium deficiency in cannabis results in symptoms on the leaves that resemble leaf septoria. Calcium deficiency causes bronze to brown spots to appear on the leaves of cannabis. If left untreated, these spots will turn red or dark. Calcium deficiency and leaf septoria can be very similar but can be distinguished by the appearance of the plant. Leaf septoriosis produces yellow spots on the leaves that turn dark brown or tan in colour. Plants with calcium deficiency have a yellow-green colour at the beginning and towards the end the leaf colour changes to reddish brown. If the spots are only on the lower leaves, it is very likely that it is septoria. This is where the fungal infection begins. By checking the pH level in the soil, you can easily tell if the plant has leaf septoria or just a calcium deficiency. A normal pH indicates leaf septoria, while a low pH may indicate a calcium deficiency. Both problems can be corrected by using the right fertiliser, but it is important not to overdo it with the amount of nutrients and additives added to the soil. Calcium, magnesium, and zinc are common nutrients whose deficiency can lead to the appearance of white spots or dots on weed leaves. Each of these deficiencies presents unique symptoms: Calcium Deficiency: Lack of calcium typically manifests as white spots on new growth. It's not zinc, I would not rule out magnesium, but I'd expect more interveinal chlorosis from magnesium which is mobile, I'd expect old growth primarily. Calcium is new growth as it is an immobile nutrient affecting new growth first, from your pics in a diary it looks like it is worse up top but you should have a much better idea, hopefully there is enough here for diagnosis.