Staff climbing pylons with live circuits experience high electric fields as they climb past the conductors. The fields are highly non-uniform because of the presence of all the steelwork in the pylon, and measuring them is made even more complicated because it's almost impossible not to have the person making the measurements distort the field further. So we don't regard the following measurements made on a UK 400 kV pylon as particularly accurate, but they do provide an indication of the order of magnitude.
In this diagram, fields are in kV/m. The red lines show the direction of the plates of the measuring instrument - so the field direction is perpendicular to them. Successive measurements are roughly half a metre further out.