The Harlequin ladybird, also known as the Halloween Ladybug, carries a fungal STI that infects other insects, has an unpleasant stink and stains furniture.
They eat other ladybirds and have even been known to bite people.
The invasion comes after seven schools in East London were shut due to an infestation of poisonous false widow spiders.
Experts say the hot summer has boosted Harlequin bug numbers.
They fly in from Asia and North America on mild autumn winds.
Since first being spotted in Britain 14 years ago, the Harlequin is now the second most common species.
It has sparked fears for native seven-spot and two-spot ladybirds.
The latter’s numbers have halved since 2004.
Swarms of the foreign bugs have been reported in Birmingham, Manchester, Norfolk, Loughborough and Gloucester.
Man United defender Phil Jones and former team-mate Jonny Evans, now with Leicester City, have both had to call in exterminators.
Jonny’s wife Helen tweeted: “They’re invading my house! Driving me mad!”
Berwyn Evans, of Rentokil, said: “The unusually hot summer created perfect conditions for ladybirds to thrive.
They seek buildings in large numbers to hibernate in over colder months.”
Brits have taken to social media to share footage of the Harlequin variety of ladybirds swarm around doors and windows.
Professor Helen Roy at the Centre for Ecology and Hydrology, who organises the UK Ladybird Survey, told BBC: “It’s quite a wildlife spectacle to see.”
She said that the reports had first started in the north of England as the weather started to turn.
It comes after the Met Office last month confirmed the sky-high average temperatures of 17.2C from June to August had made the summer a record-breaking scorcher.
Experts said it was most likely the ladybirds spotted around homes were the invasive Harlequin.
Reports of the red and black beetles have spread across the UK, with one woman in London writing: “Attack of the Ladybirds update: its officially out of hand, I’ve lost control of the room”.
What to do to get rid of Harlequin ladybirds from your home
Pest controllers have said the Harlequin ladybirds are not harmful to humans even if they do bite you.
They can be a nuisance in your home as they usually dwell in clusters and can give off a strong-smelling, staining yellow liquid.
But they can be hard to remove from your home.
It may be difficult to seal up any entrances are the insects are small but blocking up as many as possible may reduce the number getting in.
You can hopefully clean up the yellow stains by wiping the surfaces with white vinegar.
Another added they had the same problem in Warwick, West Midlands, saying: “Warwick seems to be being taken over by ladybirds. They are everywhere!!”
A third also reported: “Hundreds of #adybirds crawling all over the greenstone walls in Shaftesbury today.”
Harlequin ladybirds, scientific name Harmonia axyridis, are ladybirds that are not native to Britain.
Experts have previously said the ladybirds reach Britain by hitching a lift on the warm southerly winds.
The foreign creepy-crawlies are said to pose a threat to the domestic species because they carry a sexually-transmitted disease, called Laboulbeniales fungal disease.
They are sometimes called the “Halloween ladybird” in the US because of the time of the year they flock.
SPOT THE DIFFERENCE: What is a Harlequin ladybird?
THEY are easy to spot thanks to their bright red backs and distinctive black spots.
But there are actually 5,000 different species of ladybirds across the globe, with 46 differnet types in the UK.
The Harlequin ladybird is one of the newest insects to the block, appearing in Britain in 2004.
The beetles were introduced into mainland Europe from Asia, with it hoped they would help to control plant pests.
Thriving here, they have even outcompeted some native ladybird specifies – even known to eat other ladybird larvae.