You reported on the 1968 interview with John Lennon that I published in the New Statesman, which revolved around Lennon's "furious" response to a letter attacking him and his song Revolution for being "unfavourably compared to the BBC radio drama Mrs Dale's Diary" (Day in the life: Lennon's six-hour interview with student revealed, 17 December).

The article says Lennon was "enraged" by the letter, in "Tariq Ali's radical journal" Black Dwarf. As you say, "The Beatles might have changed their image, but had lost none of their fire, [Lennon] insisted." And in ­January 1969, in his own letter to the magazine, Lennon expressed irritation at being "ticked off" by "brothers in endless fucking prose".

But in the actual conversation – triggered when I showed him the letter, which was so patronising I knew it was bound to get him going – Lennon's response was initially dismissive, unsurprising given that this was the first time he'd seen it. He was not a regular reader of Ali's ultra-left paper: in fact the open letter to him had appeared a month before the interview.

But the idea that by the time John Lennon was shot dead in 1980 he "had long since made his peace with Tariq Ali, and regained his radical laurels", is wrong. It is true that Lennon flirted with the left in the early 70s, mainly in New York, employing his song-writing and rhetorical talents in the cause of justice and the promotion of peace.

It is therefore perhaps apt that you quote from the interview Lennon did with Ali and Robin Blackburn for Red Mole in 1971, to the effect that "Lennon agreed with Ali that he was becoming 'increasingly radical and political'".

But that was 1971. Lennon's political radicalism was in fact a relatively short-lived affair, as readers of his collection of (mostly) late 1970s writings, Skywriting by Word of Mouth, will know.

Lennon much regretted his earlier association with the radical left, as the contents of the chapter entitled "We'd all love to see the plan" (quoting from the song Revolution) make clear.

Writing in 1978, he stated: "The biggest mistake Yoko and I made in that period was allowing ourselves to become influenced by the male-macho 'serious revolutionaries', and their insane ideas about killing people to save them from capitalism and/or ­communism (depending on your point of view). We should have stuck to our own way of working for peace: bed-ins, billboards, etc."

Lennon's primary gift was for writing and recording songs that communicate with millions in ways that no ideologically driven political creed – whether of the left or right – ever could.

In the book I am writing about the relationship between Lennon's songs and his life, I explore the communicating power of his music. The book also draws on my recollections of the 75% of the Lennon interview that has yet to be revealed – your reporter could not know that what appeared in the New Statesman is far from being "the full version".