Kate, an unauthorised biography of the Duchess of Cambridge written by celebrity biographer Sean Smith, went on sale in UK bookshops today after CPI staff worked through the bank holiday weekend to deliver a "substantial print run".

Ian Smith, chief operating officer of CPI's book division, said: "There was very little information until fairly shortly before production had to begin regarding print volumes and specifications for the job and what pleased me most was that we were able to make sure that we had all the appropriate skills and equipment in place once that final specification came in late last week to cope with what was a fairly challenging deadline.

"We were even talking about changing the pagination over the weekend so it really was right to the wire, which is particularly challenging when you're producing hardback books because you need to prepare all the hard cases and put those together. Obviously that's a separate manufacturing process so you need to be extremely flexible and have a lot of firepower in those areas, where you're producing quite a complex product on a short timescale."

Smith added that the book had been a real team effort, with jackets for the hardback and covers for the paperback being producing at CPI White Quill, colour plate sections being printed and folded at Fulmar Colour, and CPI Mackays printing the text and binding the books, as well as controlling the logistics.

"From a logistical point of view, we had to have copies leaving here on bank holiday monday so it was able to be published and actually put into retails outlets and online retailers ready for sale today and we were able to hit all that distribution, which was a fairly complicated project alongside the print," said Smith.

David Hyde, supply operations director at the book's publisher Simon and Schuster, added: "We handed over finished files at 6pm on Saturday and books are on sale today (Tuesday). With this kind of book, being out on the first possible day is all important. We had total faith that CPI would deliver."

The 272pp title, which was produced in hardback and trade paperback editions, features 24 pages of colour photographs, including the shot of the couple kissing on the balcony of Buckingham Palace.