Hayfever sufferers warned as pollen bomb hits UK
Pollen levels are lower in Scotland and Northern Ireland
Hay fever sufferers are set to have a miserable week as pollen levels hit the highest level.
There is a "very high" count across parts of Wales and south England, which is forecast to continue for the rest of the week, the Met Office said.
Pollen levels are lower in Scotland and Northern Ireland, but this is expected to worsen as summer continues, forecasters have warned.
Met Office spokesman Grahame Madge said the spike has been caused by weather conditions and the beginning of the grass season.
"It is a combination of factors, partly meteorological - the sort of conditions that contribute to pollen release and spread - and also the fact that we have got the grass season," he added.
"Up to now most pollen release has been tree pollen, now we are getting into the grass pollen season in the south and it is very high."
He continued: "Some people do suffer with hay fever in extreme ways and those sensitive to pollen need to be aware that pollen levels are very high in some parts of the UK at the moment."
Pollen levels in the north of the UK are expected to increase as summer continues, he said.
"As the season progresses more grasses come out and produce pollen," Mr Madge added.
Britain faces rising temperatures - but there's more bad news on the horizon
"We would expect 'very high' annually and monthly at some times we would get to those levels.
"It is not unheard of but it is the highest category and sufferers need to take account of that."
Gin and tonic could make your hay fever a LOT better this summer
It is estimated that between 10% and 30% of adults and around 40% of children in the UK suffer from hay fever, according to Allergy UK.
Those who suffer with the condition are advised to avoid alcohol, wear sunglasses outside, keep windows closed, change clothing regularly and shower to remove pollen from hair and skin.