Tiny white spider

This tiny spider was on some plants outside the caravan this morning. It was only slightly larger than a coloured pin head. I have looked it up but can't find out what it is. Any suggestions gratefully recieved!
This afternoon my cousin and his wife came for a cup of tea on their way to Grasmere where they are going to be staying for a week. It was lovely to see them as it's ages since we last met up.