Drunken Bee's ?

All day yesterday these bee's were busy on these plants in the garden. I noticed that unlike the ones on the lavender back home, who kept flitting from one flower to another, these just seem to pick one flower and stay there.

When we went out for our walk this morning I noticed that the bees were stationary on the flower and I thought they must be dead but no, they appeared to be in a sleep like state just like a bunch of drunks who had fallen asleep after a drinking session!

I know nothing about bee's but it started to rain whilst we were out and on our return they were all gone!