The apology was made after the TMB sold out completely of its own stock of diaries, leading to disappointment for many who have tried to purchase it directly from the TMB website.
Sir Norman said: "We're big enough to admit when we get things wrong. This is the first time we have made our diary available outside of the tripe industry and we had no idea how well it would do."
The TMB sold over 50 of its 2013 diary and anticipated sales this year could rise to as high as 70 or 80 once it was made available more widely. The diary has been described as "Brilliant", "Hugely funny!" and "Hilarious", despite the TMB's attempts to convince people about the seriousness of tripe. It normally costs £5.99, but is currently available for just £5.35.
"Our own stock of 30 diaries sold out only four months after they were put on sale," Sir Norman said. "It is now only available via Amazon."
He pledged that the TMB would be "learning the lessons" but added that it was still not too late for people to purchase a copy for delivery by Christmas. "We don't want anyone to wake up on Christmas day and find themselves not having their diary, so my advice is that they act fast to avoid disappointment."