With two of the biggest events on the world SF calendar coming to town this August, others are racing to join in

London is set to be the centre of the science fiction universe this summer as the giants of the speculative literary world head for four major events spread out over little more than a week.

The big one, of course, is the 72nd World Science Fiction Convention, held from 14 August 14 to 18 August at the ExCel centre in the Docklands. If Worldcon is the venerable grandmaster of SF conferences, then the new kid snapping at its heels is the Nine Worlds Geekfest, taking place for the second time the weekend before, 8-10 August, at the Radisson hotel in Heathrow.

No doubt inspired by the fact that London is going to be stuffed to the gills with SF fans that week, two major publishers have also announced events of their own – Gollancz has unveiled a day-long festival on 13 August featuring a host of authors, while Harper's SF imprint Voyager is wheeling out a pair of big guns in George RR Martin and Robin Hobb for a post-Worldcon event on 19 August. Martin needs little introduction thanks to the Game of Thrones TV serial; Hobb is perhaps not a household name but a huge draw for fantasy fans thanks to a body of work spanning 30 years and including her latest series, The Rain Wilds Chronicles.

It could be said that London is the spiritual home of science fiction. You can trace its pedigree, winding through history like the Thames, from London-born Thomas More's 1516 breakthrough hit Utopia to Mary Shelley's Frankenstein, published anonymously by a small London publishing house in 1818, from HG Wells painting the town red (his Martians landed in Woking but generally cut up rough within the M25) in War of the Worlds in 1898 to the Michael Moorcock-led new wave of the 1960s, from JG Ballard's dystopias to China Miéville and Paul Cornell's capital urban fantasies.

Dating back to 1939, Worldcon is one of the biggest SF cons in the world, held in a different city each year, and has at its centrepiece the annual handing out of the Hugo awards. The Hugo hosts for this year have now been named as authors Justina Robson and Geoff Ryman, following the kerfuffle over Jonathan Ross stepped down from the job. The Hugo awards are only part of the show – Worldcon (given the designation Loncon3 for this year) features a jam-packed programme of author readings, writing workshops, and an astonishing 600 panels featuring more than 900 participants. Big names attending include Game of Thrones author George RR Martin, fantasy writer Robin Hobb, Audrey Niffenegger, Joe Abercrombie, Ann Leckie and many more.

London first won the bid to host Worldcon two years ago – like the Olympics, host cities have to bid for the event, and London was chosen by attendees of the 2012 Worldcon in Chicago, following a publicity and promotion campaign by the Loncon3 committee of volunteers. At that time Iain M Banks was swiftly booked as guest of honour; Banks has, of course, sadly passed away, and in tribute his life and work will be honoured with a series of events over the weekend.

There will be many at Worldcon who have attended the Nineworlds Geekfest the weekend before. A newcomer on the con scene, Nine Worlds held its inaugural event last summer, but the buzz about it is tremendous – perhaps partly because of its up-front policy of trying to disprove the hoary old cliche that science fiction is the preserve of the middle-class, middle-aged white male or – heaven forfend – the spotty teenage loner in his bedroom.

"Traditionally, con-goers are seen as the cliche – white, cisgender men," says Claire Powell of the committee. "This can lead to people who don't fall into that category feeling intimidated, or maybe even at risk. At Nine Worlds, diversity and inclusion are hugely important foundations for the event. Specifically, it aims to dump the sexism that infests many geek spaces and sci-fi cons. There is a strong anti-harassment policy and Nine Worlds endeavours to maintain a safe space for women, LGBT+ people, disabled people, and other groups that are often marginalised at geek/fandom events."

It certainly attracts a younger crowd than the more established cons. Says Claire: "Innovative and groundbreaking, Nine Worlds brings together a plethora of strands, from the more typical sci-fi tracks featuring gaming, comics, literature, fanfic and film, to Queer Fandom, Steampunk, Skepticism and Geek Feminism. Nine Worlds also hosted the UK's first academic conference on geek culture, with scholars gathering from around the country. This year, new tracks include Food geekery, Whedon, podcasting, Future Tech and Race & Culture."

It was certainly a canny move on the part of publishers Gollancz to get in on the act a couple of months ago when they announced that they were running a one-day festival at Waterstones' Piccadilly store with a roster of the imprint's authors – Adam Roberts, Joanne Harris, Patrick Rothfuss, Sarah Pinborough, Joe Hill – all appearing, and sandwiched between the two cons.

Gollancz publisher Gillian Redfearn said: "It's for fantasy and science fiction fans everywhere, and with our combination of digital and bookstore activities the festival has a real ethos of inclusivity, whether you're in Waterstones Piccadilly, on social media, or joining an interactive panel from the other side of the world. Wherever you are, come and join us on the 13th."

And Harper Voyager booked their slice of London's SF summer this week when announcing a double-header with two giants of fantasy – fresh from their Worldcon appearances – Robin Hobb and George RR Martin, to take place at a "central London venue" on 19 August, the day after Worldcon packs up.

Voyager publishing director Jayne Johnson says: "This is a uniquely exciting event, bringing together two of the greatest storytellers in modern fiction talking candidly about their writing lives. I have worked with them both for years, but in all that time I've never had the chance to eavesdrop on them in conversation: I can't wait."