Judith Kerr

Four stars

Marcel Theroux and John Gray

Four stars

Posy Simmonds

Four stars

Margaret Atwood

Four stars

Antonia Fraser

Four stars

Rapt is probably an apt description of the state of the capacity audience, many of them children, as the legendary Judith Kerr, the German-born British writer and illustrator who thinks and dreams in English, recounted her experience of her family's flight from Nazi Germany just a day before Hitler came to power - as fictionalised in her seminal trilogy beginning with When Hitler Stole Pink Rabbit. Now 90, yet as jaunty as the cats in her children's stories, she read from her 2011 illustrated book My Henry, a thinly disguised love letter to her late husband, the celebrated scriptwriter Tom Kneale, who died in 2006 after 51 years of marriage. Reading in her thin little voice the adventures of an old woman who goes off on fantasy adventures with her dead husband every day from the hours of 4pm until 7pm, with its conclusion that their ordinary life together had actually been the best thing in the world, she left most of us in tears.

"The idea of leaving this beautiful planet and our loved ones is very, very painful," declared Marcel Theroux, whose reading from Strange Bodies, his book of "speculative fiction" about a man who comes back from the dead, kicked off a difficult discussion with John Gray on the thorny subject of immortality and why we're obsessed with it. Issues of memory, identity, transhumanism and the use of technology to overcome the limits of being human had the audience laughing nervously and thinking of the Woody Allen joke about not wishing to live on in the hearts of his countrymen, but preferring to live on in his apartment.

There was a palpable sense of time standing still as Posy Simmonds illustrated the genesis of her cartoon strip The Webers, which began in 1977 and continued through until 1987 and is now the subject of a bumper hardback book entitled Mrs Weber's Omnibus. "It's just lines and dots," she said, but Simmonds' early training in graphic art and handlettering defied her rather bumbling public persona as she expertly redrew her iconic characters live in front of the audience. It transpired Gemma Bovary was based on the Flaubert classic as a way of satirising the very English middle class obsession of the time: buying second homes in France thanks to the opening of the Channel Tunnel; and Tamara Drewe, with a storyline based on Hardy's Far From the Madding Crowd, was modelled on Princess Diana.

Benji Weber would be 40 now, and his parents in their 80s. We never got round to finding out what their modern preoccupations would be, were Simmonds to start out now. I'm not so sure her creations remain undated. Perhaps it's best to leave them in aspic.

An adoring audience greeted the cult-like presence of Margaret Atwood, delivering the first-ever public reading of Maddaddam, the brilliant, challenging and chilling final book of the trilogy that began with Oryx & Crake and was followed by The Year of the Flood. The author's extraordinary grasp of that latest technological development, hacking, and a highly-honed environmental consciousness were to the fore. Her weird vision of the future was articulated with confidence. "I don't usually use things that don't already give us signs of their existence," she said, enigmatically.

Throwing out aphorisms like alms to her followers, the high priestess of terrifying possible futures ended with a note of hope. "One of the reasons for writing these books is so that these things don't happen," she said.

Antonia Fraser seemed to concur. The Catholic emancipation of 1829 laid the stage, she said, for the Great Reform Act of 1832 (the subject of her new book A Perilous Question), and it was clear that her audience would, like Fraser herself, have sided with the Whigs rather than the wealthy Tory landowners who populated Westminster at the time. Pro-reform riots up and down the country - where, incredibly, cities like Birmingham, Manchester and Sheffield had no MPs at all, and Glasgow was poorly represented - pretty much made the Bill a no-brainer, but it was twice defeated at the House of Lords and only came to pass because the Tory peers were all away at the Derby on the day the motion was finally carried in the Commons.

The historian, and daughter of the Catholic Labour peer Lord Longford, was relaxed and on top of her subject as she answered questions fielded by James Naughtie. She too had some aphorisms of her own. "Pivotal moments in history are only noted in retrospect, and we now know that the all subsequent reform comes from 1832," she declared, adding: "We must always remember that what now lies in the past once lay in the future."