This review by Alex Duval Smith appeared in The Observer (effectively the Sunday edition of the Guardian) on 1 July 2012. Ms Smith had interviewed Ken Keable and Denis Walshe in Cape Town a few days earlier. (She kindly corrected some minor errors – though still not all of them - after the article was printed and this version is the corrected one). This article did a lot to publicise the book.

A new book reveals how, in the late 1960s, just as South Africa's hated regime thought it had crushed all resistance, a group of white men from Britain packed their false-bottomed suitcases and took the propaganda war to the enemy

Denis Walshe, an electrician from Beckenham, Kent, is on a mission – to track down a black cleaner he met in a Durban hotel room in 1971. She walked in on him and his mate, Graeme Whyte, while they were building a "leaflet bomb'' designed to discharge a confetti of thousands of African National Congress leaflets they had smuggled from London in a false-bottomed suitcase.

"We had identified all the places where the black workers catch buses back to the townships in the rush hour," said Walshe, now 63. "That was where we were going to place our buckets and have them explode simultaneously.

"It was the night before and we had 10,000 ANC leaflets spread all over the floor, timing devices, electric cables and small bits of explosives everywhere and in walks the maid!

"We were in despair. We had flown halfway around the world to carry out this operation and everything depended on what happened in the next few seconds.''

Walshe, who was in his early 20s, and Smith were among a remarkably diverse group of white activists – electricians, engineers, a telephonist, a seaman and several students from the London School of Economics – recruited to travel to South Africa on a range of short missions in the 60s and 70s. Armed with toy tarantulas, fireworks and plastic buckets, they aimed to send the message that the ANC was still alive. The mastermind of the operation was LSE student Ronnie Kasrils, who later served as a minister in the governments of Nelson Mandela and Thabo Mbeki.

This motley group of men and women, all now in their 60s, have spent the last week in South Africa being feted by the ANC, and have emerged as unsung heroes of the struggle against apartheid. Whisked from Johannesburg airport to Mbeki's 70th birthday party, they were also photographed at an event with the party's centennial torch. They are on a book tour to promote The London Recruits, which charts their covert exploits between 1967 and 1971 to reinvigorate resistance to apartheid within South Africa at a time when the racist regime had jailed all the ANC's top leaders, including Mandela.

The apartheid regime thought it had stamped out resistance for good. Mandela was in jail for life, having been convicted along with the rest of the top leadership at the 1964 Rivonia trial. Other senior figures had gone into exile. Prime Minister John Vorster abolished the last four seats reserved for coloured (mixed race) MPs.

Kasrils said: "The late 1960s were the bleakest period of the struggle against apartheid. The underground networks had been crushed, we had ceased to exist and the masses were intimidated. We needed to get a message of hope to the remnants of the movement and to the South African people. The London recruits filled a void right up until 1972 when the underground was rebuilt again."

Ken Keable, a 67-year-old electrical engineer who edited The London Recruits, picks up the story: "I was studying at City University and was recruited by the London district secretary of the Young Communist League," he said. "I said I would be available after my finals in January 1968. I was introduced to Ronnie Kasrils and in April 1968 I was sent to Johannesburg on my first mission. I had 1,200 letters in a false-bottomed suitcase and had to go to the post office, buy 1,200 stamps and post them all round Johannesburg. They were letters of encouragement to the Indian community, which the apartheid government was trying to divert from the struggle.

"We were protected by our white skins. There was no reason for passport control to suspect we were working for the ANC," said Keable, who was deeply shocked at the racial injustices he found. "Some of us said we were on holiday or on honeymoon. Others, like me, looked like Englishmen looking for career opportunities. The regime welcomed people like us, they needed us. I remember thinking that if I lived here I would sacrifice a lot to bring about change. And then I thought, why only if I lived here?"

Keable's next assignment, in 1970, was to plant bucket bombs. He and a comrade, Pete Smith, were sent to Durban while other activists simultaneously carried out operations in East London, Port Elizabeth, Cape Town and Johannesburg. The leaflets stated: "The ANC says to [John] Vorster and his gang: your days are coming to an end. We will take back our country." To deter passers-by from approaching the buckets in the moments before they exploded, Keable and Smith placed joke-shop tarantulas on them.

As the buckets went off in strategic commuter sites, cassette recorders – placed in abandoned cars or bicycle baskets and wired to amplifiers – played messages from London, beginning "This is the voice of the ANC" and including songs by the ANC London choir.

"The London recruits set off leaflet distribution devices in five cities every year between 1967 and 1971," said Keable, who estimates that 1m leaflets were distributed. They were brought to South Africa in suitcases with false bottoms, two of which are known to have survived to this day, including Walshe's. It has been relieved of its normal duties as the home of the family's Christmas decorations and is touring South Africa with him.

Opening his battered blue suitcase, Walshe explained how it had been lined with white and black paper: "Ronnie Kasrils's [late] wife Eleanor had been all over London looking for the chequered paper which makes it difficult to see how deep the case is. The lining had a slit in the side which we would gently remove before cutting the fibreglass with a tin-opener."

The suitcases were the most professional aspect of the operation. Plenty of the operatives – 35 of whom have contributed to Keable's book – made mistakes. Keable accidentally detonated one of his buckets in his hotel room but by quick thinking and a fluke of the calendar he was able to tell the staff that a Diwali firecracker had been thrown through his window. AnotherOne activist flew to South Africa with a passport picture showing him wearing a Young Communist League badge.

Sean Hosey and Alex Moumbaris were both captured. In 1972 Hosey walked into a trap after attempting a rendezvous with an ANC activist who had turned informant. He spent eight months in solitary confinement in Pretoria followed by five years' jail. Moumbaris was given a 12-year sentence, but escaped after seven and a half years.

Some of the London recruits were active into the 1980s, including the owners of Africa Hinterland, a tourist company whose owners, over several years, carried an estimated 40 tonnes of weapons for the ANC in the floor of an overland vehicle. The story has been made into a film,Secret Safari.

Keable decided to write his story in 2005. "I was coming up to my 60th birthday and I asked myself what I would regret not doing, the day I felt death approaching. It took me three days to write my story, and when I had finished I realised mine was one among many stories, so I began tracking down other recruits." Keable is "on the tail" of several others but has not found them all. He added that some recruits have refused to give their stories while others have written under a pseudonym.

The book is also a call for greater international solidarity. "All the London Recruits could have said apartheid is wrong but it's not my problem, but none of them did. With every passing day the world is more interconnected but this also makes it increasingly untenable to think that a problem faraway is not my problem. International solidarity is something we need more and more of now, for the people of Palestine or for the people of Saudi Arabia."

Walshe echoes his call but has not forgotten his other priority during his upcoming four-week holiday – finding the hotel maid. "She was about our age and black. Pete and I were so shocked when she came across us in the hotel room that all we could think to do was the ANC salute. We were supposed to be as white as can be. We were not supposed even to talk to any black people during our visit. Instead we told her everything and our operation grew from two people to three. We said goodbye with a kiss, which was about as illegal as you could get in those days. I would love to meet her again."

• This article was amended on 2 July 2012 to correct references to Pete Smith and Graeme Whyte and to restore text lost in the editing process.

Buy book here

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