Boris Johnson auctioned off by Tory colleagues without his knowledge

The mayor of London was among the lots offered to guests at the glamorous Black and White Ball, which raises funds for Conservative coffers.

But Conservative HQ failed to inform Mr Johnson and mayoral commitments might prevent him from taking part.

Bidders were told that the mayor would "enlighten and delight " the purchaser with talk of Winston Churchill - the subject of his most recent book- over a cup of tea.

Mr Johnson said: "When Conservative central office are kind enough to enlighten me about this offer, I'm sure I will be delighted to accept, mayoral commitments permitting, which they may not."