The Met Office is urging households to stockpile one key item before this Wednesday.

The weather experts have told those suffering from hay fever that it ‘might be time’ to ‘stock up’ on antihistamines because of a fresh batch of red pollen warnings arriving from July 9.

The forecaster says that grass and weed pollen – two key red flags for hay fever – are set to be high or very high for the rest of this week, starting from Wednesday.

Even those up north in Scotland won’t be spared, with high warnings in Edinburgh from Wednesday, turning to very high by Friday.

Down south, in London and Exeter, very high warnings will be in place from Wednesday, while Leeds in West Yorkshire will see high on Wednesday and very high warnings on Thursday and Friday. Over in Northern Ireland, high warnings will be in place all three days.

The Met Office said: “Hay fever sufferers, it might be time to stock up on those antihistamines.

“Grass and weed pollen levels are forecast to be high to very high this week.”

In its advice on hay fever, the Met Office says: “Depending on the time of year, the type of pollen in the air will be different. There are around 30 different types of pollen that cause hay fever and it is possible to be allergic to more than one type.

“Most people are allergic to grass pollen, which is common in late spring and early summer. Tree pollen tends to be released during spring and affects around 25% of people. Weed pollen can be released at any time from the early spring to the late autumn.

“Hay fever symptoms usually appear when the pollen count, which is a measure of the number of grains of pollen in one cubic metre of air, exceeds 50. The weather conditions affect how much pollen is released and spread around. On humid and windy days, pollen spreads easily but on rainy days, pollen can be cleared from the air. On sunny days, the pollen count is highest in the early evening and that’s when you are most likely to suffer from hay fever symptoms.”