Video courtesy of Richard Wheeler
The London mayor erupted in laughter when he saw the sign, which read: “WE LOVE YOU BORRIS”.
He said: “I think it’s better like that. I think I might change it. It’s less confusing. It’s a proper English spelling really.”
Director Bernice Colwell said: “He was great. He had a good old chuckle.
“We weren’t expecting him and someone said ‘Boris is there,’ so we quickly did it.
“Somebody said it and with that everyone went into action and the guy that did it just sort of did a typo, but it was quickly remedied.”
She added: “Boris thought it was hilarious and we’ve still got it in the office now.”
Lord Jug, who is contesting the same seat as Mr Johnson in the upcoming General Election, said: “I tried to actually get some out and put it on his head, but I found it wouldn’t go on because he’s very slippery anyway.”
Lord Jug also offered to surrender the leadership of his party to his Conservative rival if Mr Johnson does not win on May 7.
Mr Jug said: “He looked a bit confused, to say the least.
“He said: ‘I’m highly honoured, your lordship. I may have to consider this for another time, but not at this election.'”