Flies are more than a nuisance. They feed and breed on waste, then land on food and worktops, carrying bacteria with them. Several different flies turn up in London homes and businesses, and each one breeds somewhere different, so identifying the fly is the fastest way to find and remove the source.
House fly
6 to 8 mm, grey with striped thorax
Bluebottle
10 to 14 mm, metallic blue
Fruit fly
3 mm, tan with red eyes
Cluster fly
8 to 10 mm, slow, golden hairs
Peak season
May to September
Common Flies and Where They Breed
- House fly (Musca domestica): grey, 6 to 8 mm, with four dark stripes behind the head. Breeds in rubbish, food waste and animal droppings.
- Bluebottle and greenbottle (blow flies): large, noisy, metallic flies. They breed in meat and dead animals, so a sudden swarm indoors often points to a dead mouse, rat or bird nearby.
- Fruit fly: tiny, tan flies with red eyes that hover around fruit bowls, bottle bins and drains. They breed in fermenting fruit, spilled drinks and food residue.
- Drain fly: small, fuzzy, moth-like flies that breed in the slime inside drains, overflows and waste pipes.
- Cluster fly: slow, dull flies that gather in lofts and around window frames in autumn to spend the winter. They breed outdoors in soil, not in the house.
How Did I Get Flies?
Flies follow smells. They come in through open doors and windows, drawn by food, bins and pet waste, and they stay if they find somewhere to lay eggs. A house fly can lay several hundred eggs in its short life, and in warm weather the eggs can become adult flies in little more than a week, so numbers build very quickly.
How Serious Are Flies?
Flies feed by vomiting digestive juices onto food and sucking up the liquid, and they leave droppings wherever they land. Because they move between waste and food, they can spread bacteria such as Salmonella, E. coli and Campylobacter, which cause food poisoning. In restaurants, cafes and shops, flies are a food safety problem and can affect hygiene inspections.
Signs of a Fly Infestation
- large numbers of flies around bins, drains, windows or light fittings
- clusters of small dark spots (fly droppings) on walls, ceilings and light shades
- maggots in bins, food waste or pet food
- flies returning day after day even with the windows closed
How to Prevent Flies
- Cover food and clear away leftovers straight after meals.
- Keep bins sealed, empty them often and rinse them out, especially in summer.
- Clean drains, sink overflows and the area under kitchen appliances.
- Clear up pet waste in the garden promptly.
- Fit fly screens to kitchen windows and doors that are left open.
- Find the source. Killing the adult flies will not help for long if the breeding site is still there.
Flies you cannot get rid of?
Our fly control is a 2-visit treatment from £200 + VAT for a 1-bedroom property, including an inspection to find the source. You pay after the service, not before.
See Fly ControlCall 020 8106 5666Frequently Asked Questions
Why are there suddenly lots of big flies in my house?
A sudden swarm of bluebottles usually means something has died nearby, such as a mouse or bird in a wall, loft or chimney. The flies bred on it and have now hatched.
Why do flies gather in my loft in autumn?
These are usually cluster flies. They come indoors in autumn to shelter for the winter and often return to the same building each year.
How do I get rid of fruit flies?
Remove what they are breeding in: overripe fruit, empty bottles, spills and residue in drains and bins. Without a breeding site they disappear within days.
