Having problems with a weed growing all over my garden

We have this weed growing over my garden and even once used weedkiller seems to make a rapid return, I have taken a couple of photos for advice on what weed this is and the best weedkiller to get rid of it.

Thanks for any help

 

Is it one of the Epilobium tribe? Codlins and Cream?
We have tons of it, pulling them out is easy enough and you must do it before they set seed. Trouble is the more you pull the smaller the remaining ones are before they flower. We have some now at 2 inches setting seed.

 

Thanks for the reply I usually do keep pulling them out, before I went on holiday there was hardly any and came back to a load of it and thought where the hell has all that come from lol. Will try the weedkiller again and pull them out once dying

 

I'm forever pulling those out. Thankfully they are pretty easy to pull up but still a pain.

 

Not something for weed killer are my thoughts, its an annual, so best hoed out at an early stage.