Yellow Ragwort. 

Native Superwildflower, this is Yellow Ragwort.
Every summer there is always scaremongering about our incredible native wildflower that has been here since the last ice age.
A lot of the scaremongering originally came about In 2002 when the British Equestrian & Veterinary Association and the British Horse Society carried out a survey on effects of Ragwort, the survey was proven to have been based on bad science, so much so that they ended up removing that article and survey from their website.
But sadly this miss-information has stuck
This video on RU-vid
• Yellow Ragwort.