The evergreen Harry Potter franchise and the popularity of TV chef Tom Kerridge’s Lose Weight for Good has driven book publisher Bloomsbury’s revenue to the highest level in its 32-year history.

Bloomsbury Publishing reported a 13% surge in revenues to £161.5m in the year to the end of February, its best performance since it was founded in 1986.

Investors sent shares in Bloomsbury, which reported a healthy pretax profit rise of 10% to £13m, up nearly 9% to their highest point since early 2007. That was the year the last of JK Rowling’s original seven-part Harry Potter series was published, helping drive annual revenues to the previous record of £150m.

Sales of the Harry Potter series grew 31% year-on-year, helped by special editions of Harry Potter and the Philosopher’s Stone, and Fantastic Beasts and Where to Find Them.

The continued popularity of the franchise helped drive sales at Bloomsbury’s children’s division by 24% to £69m, with the publisher’s biggest-selling book of the year a new illustrated edition of Harry Potter and the Prisoner of Azkaban.

Nigel Newton, the chief executive and co-founder of Bloomsbury, said the popularity of the boy wizard showed no sign of fading.

“You could almost say that the Harry Potter series is increasing in popularity,” he said. “If you put aside the years that the first books were being put out – those sales will never be rivalled – sales have never been higher.

“The enduring appeal of JK Rowling’s writing as new generations of children come along to take up their parents’ favourite book is continuing to make Harry Potter more widely read than ever.”

Bloomsbury said that it also saw significant success with Kerridge’s Lose Weight For Good, and Sarah J Maas’s A Court of Wings and Ruin.

Newton said Kerridge’s book set a UK record for selling the most copies in a week in January, as New Year resolutions were put into practice.

“We have signed a contract for Tom’s next book too. We hope it will be as big as this one,” he said. “It will come out in December ahead of the New Year when people are filled with worthy resolutions for health, good food and fitness.”

The company is continuing to receive a fillip from sales of the The Guernsey Literary and Potato Peel Pie Society, thanks to the film version of the historical novel it first published a decade ago, starring Downton Abbey actor Lily James.

Bloomsbury, which listed on the stock market in 1994, has enjoyed a share price rise of almost 30% over the last year.

Newton said this was the result of a strategy to broaden the scope of the publisher’s business and build digital revenues as well as academic and professional publishing operations.

He said total digital revenues rose 13% to £18m and that within that “digital resource sales” – such as selling the Churchill archive online to academic libraries – rose 20% to £4.7m.

“We have been seeking for 10 years now to create a balanced portfolio between general publishing and academic and professional publishing,” he said. “What you see coming through in the results is that the fruits of that strategy.”