Intelligence agencies more than any other professional body have “official amnesia” and repeatedly fail to learn the lessons of the past, a panel of espionage experts has said.

Christopher Andrew, the writer of an authorised history of MI5, said intelligence chiefs ignored or did not know about historical mistakes, and the reason was obvious: the operations were always secret.

Referring to friends and Cambridge colleagues who had worked at Bletchley Park, he said: “None of them knew that what they had been doing in the second world war, breaking Hitler’s codes, was much what their colleagues had been doing at the beginning of the 19th century, breaking codes with equal success. No profession is as ignorant of its history as the profession of intelligence.”

Andrew said neither Herbert Henry Asquith nor Woodrow Wilson, the UK prime minister and US president respectively during the first world war and two of the most highly educated people to hold office, knew anything about intelligence. If George Washington had used intelligence in the same way Wilson later did, the American success in the war of independence would have taken much longer, he said.

Andrew was speaking on a panel at an event headlined The Spying Game at the Cheltenham literature festival on Monday. On the subject of waterboarding, he said: “The absurd attempt by some people, whether the CIA or George W [Bush], to claim that it wasn’t torture … well, the Spanish inquisition, which invented it, could have told them it was torture, and it didn’t work. Intelligence is, more than any other profession, one in which it is possible to go backwards.”

He said the Salisbury poisonings in March were “nothing new”. KGB assassination attempts 50 years ago during the cold war were “so incompetent that they called them off for over a decade”, he said.

Rory Cormac, an academic in international relations, said he had searched laboriously through 50 years of archive material looking at how intelligence services operated and had found them doing one thing for a year, realising it did not work, and then people moving on and the service going back to what it had been doing. “They are constantly failing to learn from their mistakes.”

He said he was in Whitehall last week and offered some suggestions but was rebuffed.

There have been suggestions that the Russians have deliberately tried to make the Salisbury case look farcical. Gordon Carrera, the BBC’s security correspondent, said he did not believe this was so and that there were dangers in not taking the attack seriously.

“The one risk of treating it as comedy, as farce, is that there are serious things going on at the moment and some of those are linked to Russian intelligence.” There was a danger of those being overlooked, he said.

Andrew said: “The one thing that can be said about the Russians is that they take, for better or for worse, a longer view of intelligence than any western agency.”

Annie Machon, a former MI5 officer, said she thought there was a “hysteria” over Russia that was disingenuous when British and American intelligence services had been guilty of similarly bad behaviour.

“The Snowden disclosures were only five years ago, showing, indeed, our intelligence services were doing the same things as the rest of the world, and for us to clutch our pearls and say, ‘Oh my God, the Russians are bad and we’re good’ is, I think, slightly disingenuous,” Machon said.

Machon, the former partner of the MI6 whistleblower David Shayler, said western spy agencies were frequently guilty of allowing things to “spiral out of control”.