It is a pleasure to thank P. N. Best, J. Dennett-Thorpe, H. J. Hardcastle and M. Lacy for valuable discussions. I would also like to thank P. N. Best and A. P. Schoenmakers for help with the reduction of the radio data and J. Dennett-Thorpe for providing the maps of 3C 219. Many thanks to the anonymous referee for valuable comments.
© European Southern Observatory (ESO) 2000
Online publication: October 24, 2000