How do I get rid of a persistent weed in my lawn?

could try weed and feed maybe?

If the lawn is slightly damp then it may be Mind Your Own Business- the leaves are about 5mm wide. Once you have this weed, although some grow it as a plants, you've got it im afraid, Try a hormonal lawn weedkiller that will kill of broad leaved weeds. Dont compost the weed, burn it or dispose of carefully as it can choke streams and rivers etc. Burnings best!! or in a bin bag in the normal bin.