A key Commons statement by Margaret Thatcher which helped trigger her downfall may have been influenced by a news story written by Boris Johnson which was ‘not quite right’, newly-released documents suggest.

The story, published on October 24, 1990, and written by Mr Johnson when he was the Daily Telegraph’s Brussels correspondent, was about European Commission president Jacques Delors.

It was headlined ‘British Right Of Veto Faces Axe In Delors Plan’ and Mrs Thatcher marked two lines beside the headline on a cutting of the article in her despatch box file.

Thatcher Foundation
Margaret Thatcher with Jacques Delors

She also marked two lines beside a paragraph which read: “M Delors said the plans were intended to pave the way for a Federation of Europe, a super-state with the Brussels Commission as the executive government and the Council of Ministers as a senate.”

But Chris Collins, from the Margaret Thatcher Archive Trust which is making the documents available to the public, said Mr Johnson’s article was “not quite right”.

A memo written two days later by senior Foreign Office official Richard Gozney to Mrs Thatcher’s Private Secretary Charles Powell, and also kept in the Number 10 file, noted: “The Commission Opinion itself… does not contain what M Delors is reported by the Daily Telegraph as having suggested.

“It does not propose any radical change in the present institutional plans of the Community – although it does contain a lot of other horrors.”

On October 30, Mrs Thatcher made a House of Commons statement in which she defiantly declared “no, no, no” to M Delors.

The statement came during a time of intense division in the Tory party over Europe and proved too much for Sir Geoffrey Howe, who quit as leader of the Commons and deputy prime minister days later and made a devastating resignation speech from which Mrs Thatcher never recovered.

She was ousted a few days later.

Sir Geoffrey Howe
Sir Geoffrey Howe quit as deputy prime minister days later (PA)

Mr Collins said Mr Johnson’s article was “not quite right” and Mrs Thatcher “knows it’s not quite right”.

But he added:  “A lot of Conservatives would read articles like that one by Boris Johnson – I’m sure it wasn’t the only one written at the time – and say ‘yes, that’s what these guys (in Brussels) are up to’.

“Those pressures are all around her and she is treading this terribly, perilously difficult path.

“It’s not clear that she wanted a war, as it were, and yet she feels many of these things too and she’s got this sinuous route to follow.

“While I’m not saying this is the cause of her downfall or anything like that – it would be absurd to suggest that – the forces that are in play are somewhat revealed by the presence of that article.”

The Margaret Thatcher Archive Trust is gradually overseeing the release of her private files through the Churchill Archive Centre in Cambridge.

Members of the public will be able to browse the archive from Saturday by visiting www.margaretthatcher.org.