The "racist" English Defence League (EDL) was useful to Lutfur Rahman, Election Commissioner Richard Mawrey suggested.

Mr Mawrey said the EDL disliked Mr Rahman and repeated any criticism of him on social media.

That enabled Mr Rahman to argue that anyone who criticised him was "giving aid" to the EDL.

"All parties agreed - and it is probably a matter on which judicial notice may properly be taken - that the EDL was an overtly racist organisation, particularly hostile to Muslims," said Mr Mawrey.

"But the EDL does have its uses.

"Because it dislikes Mr Rahman - undoubtedly, in the case of the EDL, because he is non-white - the EDL seizes on any criticism of Mr Rahman and repeats it on social media.

"This enables Mr Rahman and his cohorts to argue as follows: criticisms of Mr Rahman by his political opponents are adopted and repeated by the EDL: the EDL is a racist organisation: therefore anyone who criticises Mr Rahman is giving aid and comfort to the EDL: therefore anyone who gives aid and comfort to the EDL is himself a racist: therefore it is racist to criticise Mr Rahman.

"This series of propositions informed all the responses of Mr Rahman and his team to criticisms."

He added: "Truly, in Tower Hamlets, if the EDL did not exist, like Voltaire's God, it would be necessary to invent it."