Rabbiofberlin – unfortunately everything you have written is correct. The chillul Hashem that some of the people who were most active in the opposition to the eruv have been responsible for recently is beyond description.
I have more respect for Rabbi Roberts than I do for all the other eruv opponents put together and I will endeavour not to discuss specifics, but if you think politics is absent from the discussion here you are deluding yourself. I am not interested in pushing this point – let’s stick to halacha.
I am sure that if he had anything to add to the arguments against a London eruv this would have been included in the anti-eruv kuntres published by his junior colleagues. The weaknesses of this publication have been demonstrated elsewhere.
I should add that the Tzitz Eliezer is referring to Rabbi Roberts when he says that the mesaknei ha’eruv should take no notice of those who want to prevent the eruv being built for various reasons, and that they have a ‘chiyuv’ to establish the eruv as soon as they are able to.