The Communities Secretary failed to declare the meal because he claimed he was eating privately.
Labour MP Paul Flynn raised the issue in local government questions yesterday. He said: 'Even though a five-star dinner at the Savoy, which was paid for by the lobbyist Bell Pottinger, had in attendance at least one firm which made an application to his department, the Secretary of State says he has no reason to register that in the Members' Interests because that day he was not eating as a minister, he was eating as a private person.
'If we are to have a robust, transparent system of lobbying, do you think this loophole has to be closed so we don't have to guess on which day Members are eating privately and which days ministerial?'
Before Pickles could defend himself, Speaker John Bercow intervened: 'I wanted to hear the question, but the registration of Members' Interests is undertaken by Members in their capacity as Members, rather than as Ministers. I suspect that there will be a correspondence or exchange subsequently, but that is my understanding of the position.'
Questions over Pickles' attendance at the dinner were first raised on 22 October by the Bureau for Investigative Journalism, as part of an investigation with The Sunday Times into loopholes in ministerial transparency rules.
The bureau was alerted to the dinner by a blog posted by Bingle. 'The discussion must remain private but I can reveal that the guests were more than just impressed,' he wrote.
Bingle has subsequently stopped his 'musings' and the BPPA blog is no longer live.
Last night, Bingle rejected suggestions the dinner was meant to be hidden from the public eye. He said: 'How is a dinner with Eric Pickles secret when I talk about it in a musing?'
He added: "The public affairs industry has a paradox. When is a secret dinner not a secret dinner? At a time when there are calls for public affairs consultants to be more transparent it is slightly ironic to then be attacked for having mentioned a ministerial dinner for clients in a musing in February.
'Our critics always assume the worst about everybody. The politicians that I deal with are good and decent people who I both like and respect. In all my twenty-five years years in this business I have never been let down by them. They have never broken a confidence or betrayed a friendship. I trust the same is true of me.'
A spokesman for Pickles said today: 'The Secretary of State attended the dinner in a private capacity and therefore was not required to declare it. He therefore met the requirements of the Ministerial Code.'