Despite a stonking £30 RRP, the latest Robert Galbraith – pen name of Harry Potter author JK Rowling – has gone straight to the top of the Official UK Top 50, according to the latest data from NielsenIQ BookScan’s Total Consumer Market (TCM)..

A total of 53,207 copies of The Hallmarked Man (Sphere) were sold in its first week on sale – with its average selling price (ASP) of £15.47 a little under half price – making it the fourth biggest number one of the year behind Onyx Storm by Rebecca Yarros (Piatkus), Sunrise on the Reaping by Suzanne Collins (Scholastic) and World Book Day title Bluey’s Little Book (Ladybird).

The Hallmarked Man is the eighth in the Cormoran Strike series and while it has not quite matched the series’ biggest first week sales – Troubled Blood sold 64,663 copies back in September 2020 – it has managed to beat the previous title in the series, improving on 2023’s The Running Grave’s 50,925 copies by 4.5%.

Galbraith dethrones RF Kuang from the number one spot, pushing Katabasis (HarperVoyager) down to seventh in the TCM following an 82.8% drop in sales in its second week. With 7,521 copies sold in the past seven days, Katabasis does hang onto second in the Original Fiction Top 20 (OF), just ahead of Adam Kay’s A Particularly Nasty Case which notched up 6,204 copies this week – 55.5% down on its launch week.

Runner-up in TCM Top 50 is Fearful (Simon & Schuster), the second companion book to be released for Lauren Roberts’ Powerless trilogy. With 16,518 unit-sales, it is someway off Galbraith’s figure, but it is enough to snare the Children’s number one, even if it cannot match the 43,087 copies that the concluding part to the trilogy, Fearless, managed in April this year.

AF Steadman’s Skandar and the Spirit War sheds 74.1% of its sales week-on-week to drop to fourth in the Children’s chart with 4,702 copies, following its debut in pole position. Coco Wyo’s Cozy Corner sticks in second place with 5,333 copies, just 186 units ahead of JB Priestley’s An Inspector Calls which has seen sales rise 159.8% as the reading list staple makes its annual return to the bestseller list.

In a week with no new releases bothering the Mass-Market Fiction Top 20, Freida McFadden has managed to retain first place for a third consecutive week with sales of 11,246 units for The Surrogate Mother (Poisoned Pen Press), a slight drop of just 2.2% on the previous seven days. Although once again, combined sales of both editions of the Netflix-boosted The Thursday Murder Club (Viking) would have given Richard Osman a number one with a total sales 12,379 copies, a 2.9% increase on the week before.

Following a fairly static couple of weeks in the Paperback Non-Fiction chart, there is a bit more movement in the latest data, although Gillian Anderson does retain her crown with Want (Bloomsbury) for a seventh consecutive week – although there is a gap of just 172 books between it and second-placed Minute Cryptic by Angas Tiernan and Liam Runnalls, a step-by-step guide to solving cryptic crosswords which shifted 3,561 copies in its first few days on sale.

The avalanche of new releases in the Hardback Non-Fiction chart continues – there were nine newcomers in the previous chart and another 10 debutants this week – ably led by Julia Bradbury’s Hack Yourself Healthy (Piatkus). The TV presenter and breast cancer survivor’s latest moved 5,720 copies, grabbing the HBNF number one, giving Bradbury a 34.3% increase compared with the first week of Walk Yourself Happy from September 2023.

For the second week in a row, the new releases have boosted the market with volume sales up 3.3% on the previous week to 3.4 million books, with value increasing 3.6% to £32.8m. Compared with the same week in 2024, however, volume is down 5.3%, with value slipping 2.4%.