This is the larvae of a Hover Fly, probably a Volucella Sp. They feed on the remnants of wasp nests and as such if they are found in the home an old nest is normally nearby.
Best wishes Lewis
This looks like a Volucella inanis larva to me. The book gives the number of crochets on the prolegs 6-8, and here I see 9? The larvae come out of wasp nests where they live as ectoparasites of wasp larvae and spend the winter in a hide. They will pupate in spring and emerge as beautiful wasp mimics.
Thanks for these great close-ups!
I have checked again and it seems that it is Volucella inanis after all. They say that it is different from all the other Volucella by being flattened dorso-ventrally and having a smooth body surface. So no transverse rows of settae and lateral projections which give the 'hairy' aspect to V. zonaria larvae. Also only 3-4 crochets per proleg, and they are longer in the case of V. zonaria. There was an older post and you can compare the photo there. I'm attaching a quick scan of V. pellucens larva for comparison.
Thanks Florin. 'Just putting it out there' I remember being facinated by these larvae ( V. pellucens ) the first time I dug up a wasp nest. A hairy business for a 10 year old.
My cruelty as a ten year old still amazes me. To unearth the beautiful football sized nest from an earth bank at the bottom of a friends garden i used a large R Whites lemonade bottle (2.5 p on return) full of paraffin and petrol poured directly into the entrance and lit, plus myself and two friends with badminton racquets to deal with subsequent returnees and survivors. This was all because an article in the then Anglers Mail said that wasp grubs were THE bait to have when in search of elusive large Chub.
Thanks very much for your very helpful replies. We have had a large wasps nest in one of our chimneys and several of these bugs have fallen down and have been crawling across the floor. As I love hover flies I will treat them with great respect.