There are more than 650 species of spiders in Great Britain, so it's not uncommon to find several different spiders in a person's house at any given time. While some of these spiders can appear quite nasty, they are relatively harmless to people and give the added bonus of keeping the insect count down.
One of the most common house spiders in Great Britain is literally named the house spider. The house spider's scientific name is Tegenaria domestica. These are fairly large and hairy spiders that can measure up to 10 mm in length. They have a reputation for liking moisture, so are often found in the house in the shower or bathtub. The house spider is not venomous and is not dangerous to humans despite its intimidating appearance. They prey on many local pests, such as flies and mosquitoes.
The garden spider (Araneus diadematus) is one of the largest spiders in all of Great Britain, and since it is often found in small gardens, it is not uncommon to find some of these spiders wandering in local houses in search of a good place to set a web. Females can reach a size of 18 mm, which is twice the top size of males, which stop at 9 mm. Garden spiders can actually vary quite a bit in colour from dark brown to bright red and every shade in-between. Garden spiders are known for having a distinctive white "cross" on their abdomen that makes them easy to identify.
Missing Sector Orb Weaver
The missing sector orb weaver (Zygiella x-notata) is a smaller house spider that is actually found more often in homes or buildings spinning webs in corners or by windows as opposed to being outside. The webs these spiders weave are very distinctive, as it is an orb web that is missing a whole sector, hence the name of the spider. The other characteristic that makes these spiders noteworthy is that they are particularly active in the winter when most spiders are not.