I have suffered from the same problem, there were none one day then i cut the grass and the next thing they were all over the place. Dont know if doing the lawn had anything to do with it or it was just a coincidence.
The little darlings make a beeline for a combination of open windows and lights, more prevalent after a spell of wet weather.
As jonnythe bosh has found the larva (leatherjackets) will live happily in your lawn muching away at your roots and stems until they turn into Daddy Long-Legs. Harmless, but I still don't care for those long dangly legs!
There do seem rather a lot this year. These things do tend to go in cycles and obviously it's been a good year for daddy long legs. Other years you'll find there are a lot of ladybirds or something else.
I think I am right in saying that the Daddy Long Leggs is one of the most venemous creatures to be found, however it does not have any method of delivering the venom and it only contains a tiny amount.
I may be proved wrong on this but I picket up that little snippet somewhere.
You are right in a way RATTER15. It is the most venomous creature in the world - but at the same time completely harmless.
The British DLL or Cranefly is an extremely fragile flying insect and harms no one or anything....but in the United States they refer to a Cellar Spider as Daddy Long Legs and this is the venomous one, although it's mouth is so small that it doesn't bite but lives on tiny insects and bits of plants.
lol x I'm laughing, watch me blooming end up dreaming about them, yuk, I'm off 2 bed now 2 scared to open window and hav a ciggie, think i will choke on the smoke instead, lol, oh and spiders even worse, time for a Nytol x