The Guardian has admitted that a cartoon about the Israel-Gaza conflict portraying a grotesque Benjamin Netanyahu as a puppet master controlling William Hague and Tony Blair "inevitably" echoed "past antisemitic usage of such imagery".

Although the paper initially chose not to comment on the image, which sparked accusations from the Community Security Trust that cartoonist Steve Bell had employed an established "antisemitic trope" in his drawing, the matter was addressed by Readers' Editor Chris Elliot last weekend.

Writing that Mr Bell tended to give offence in his work, Mr Elliott noted the attacks on the cartoon were recorded "on websites that are pro-Israel and aimed at the Jewish community". He also referred to other occasions on which Mr Bell has used the theme of a puppet master, in cartoons featuring Presidents Mubarak and Putin.

Mr Elliott said it was an "incontrovertible fact" that in the 1930s and 1940s, Nazi propaganda about Jews featured "a grotesquely drawn Jew shown as a puppeteer, with exaggerated features"."

"The image of Jews having a disproportionate influence over the US and British governments has often been replicated by anti-Jewish cartoonists in the Middle East since the end of the Second World War."

He said that while Mr Bell was not antisemitic, nor had he intended to draw an antisemitic cartoon, "using the image of a puppeteer when drawing a Jewish politician inevitably echoes past antisemitic usage of such imagery, no matter the intent".

"The Holocaust and its causes are still within living memory," added Mr Elliott. "While journalists and cartoonists should be free to express an opinion that Netanyahu is opportunistic and manipulative, in my view they should not use the language – including the visual language – of antisemitic stereotypes."

Included in the readers' editor's column was a comment from Mr Bell, who repeated his denial that the cartoon was antisemitic and said that "once people start dignifying this utterly unfair and unreasonable comparison with faux intellectual terms like 'antisemitic trope' it blots out the fact that my cartoon lacks the central 'trope' of actually being antisemitic."

"It does employ the trope of 'puppeteer', but that is a trope, not an antisemitic trope," he said.