Petty spurge/milk weed, unless you want your garden covered in it and your plants weakened, pull it up now! Seeds can lie dormant for up to 100 years. I'm forever pulling the stuff up, wear gloves though because the sap is an irritant.
@anne8691 Hello! Where did you spring from 😃Thank you so much. I've got a few to pull up but this one is the biggest (which is not very) I really appreciate your help. Thank you again. I love my plants and garden too much as we all do on here, to see anything horrid thing harm them. The darn thing is sat proudly in my new patch surrounded by pretty things!! 😮Out it comes!!😈