Is this the worst place in London to have a picnic?

As you'll know by now, London is set to be hotter than Ibiza this weekend. But the sun has already started shining and Londoners are making the most of it - including this group in Greenwich. They had a picnic this lunchtime in a parking space in Greenwich.

They even used a traffic cone to help keep cars out. Is this the worst place to have a picnic?