After the bumper crowds seen at Letchworth’s David’s Bookshop the last time a top children’s author came to town, there’s likely to be a more sedate response when Robert Muchamore visits later this month.

But he’d be the first to admit that he’s not yet in Jacqueline Wilson’s league – at least in this country.

There’s no denying that he’s up there in the bestseller lists when it comes to junior fiction, though, and there will be keen interest in his latest book – and final Cherub novel – New Guard.

The series of high-octane spy yarns stretches back a dozen years and takes in 18 titles, which between them have racked up more than 14 million sales worldwide – figures that would raise an eyebrow even for Tracy Beaker author Jacqueline, who might be considered more of a homeland hit.

Muchamore is credited with helping to turn the spy genre into arguably the biggest children’s publishing phenomenon of the new millennium, reaching out to that army of famously ‘reluctant readers’ – boys aged 11 to 15 who wouldn’t be seen dead with a Beaker in their back pocket.

In the final Cherub instalment the young hero of the original series is now a mission controller and leaps across to land among the characters of the spin-off Aramov string where another young hopeful is about to embark on a life or death mission with agents old and new.

Their aim is to bring two kidnap victims home alive – but when Islamic State fanatics make up the opposition, it’s not going to be easy.

Muchamore famously commits to answer every single email and letter from his readers and has helped many to dip their toes into the world of publishing and start out as writers themselves.

The signing session at the Eastcheap store on Wednesday, June 22, has been timed neatly for 4pm, handy for an after-school appointment. Fans can reserve a signed copy in advance for £10.99 or turn up on the day and pay the cover price, which is £2 more.

To find out more call 01462 684631 or visit www.davids-bookshops.co.uk.