Bernard Ingham: A sudden departure... and a lingering mystery

It also carries to this day a warning for a coalition that finds Europe a potentially divisive subject.

I was so close to the epicentre of this upheaval in Thatcher's second government that there were plenty ready to blame me if, as she briefly feared on the day of reckoning – a Commons debate on, yes, the Westland affair – she was hounded out of office.

It never came to that because Labour's leader, Neil Kinnock, not for nothing called the Welsh Windbag, comprehensively blew the case for the prosecution, such as it was.

First, the mystery. Why on earth did Heseltine choose, as Defence Secretary, to pursue to the death the idea of merging the troubled Westland helicopter company, not exactly a commanding height of the economy, into a European consortium?

The Cabinet was not with him. The consortium did not even exist and never materialised. Yet he brought to his campaign all the verve I had learned to admire when he routed the CND over the deployment of cruise missiles in Europe. Frankly, Leon Britain, the Industry Secretary, was no match for him as upholder of the Cabinet's view that Westland should find its own salvation. It eventually did with the American Sikorsky, though, ironically, it is now in the Eurocopter group with Italy's Agusta.

Brittan became so exasperated that he sanctioned the leaking of an otherwise innocuous letter from the Solicitor General to Heseltine. This missive, the product of discussions involving Thatcher, pointed up what were termed "material inaccuracies" in one of the Defence Secretary's blizzard of communications that surfaced in the press. Unfortunately, Brittan's agent asked me to leak the letter. I refused point blank, saying I had to keep the PM above that sort of thing. But, by then, I had been embroiled in what was portrayed as underhand work aimed at the downtrodden Heseltine who was by then complaining that "She who must be Obeyed" was stifling Cabinet debate.

On this evidence, David Cameron's coalition, Cable and all, is a model of purposeful unity.

The stench of hypocrisy in all this was overpowering. First, the media, which thrives on leaks and worships whistleblowers, came over outraged at government incontinence. Yet who had assiduously been using them during the row? Why, St Michael himself.

And when is a leak not a leak when, within certain rules, disclosure is authorised by a Minister? This was only technically a leak because Brittan had not consulted fellow Ministers before making the fateful letter public.

Worse still, journalists told me that the Attorney General, Sir Michael Havers, was giving a running commentary on the affair at the bar of the Garrick Club. When Havers had the temerity to lecture us in No 10 about the unacceptability of leaks, he got a very hard stare from me.

In spite of all this, nobody expected Heseltine to make his dramatic exit. Nor, in flouncing out, did the great communicator make his intentions entirely clear. So I had to dispatch press officers to Whitehall's phone-boxes to ask reporters what he had said.

His resignation confirmed, George Younger, then Scottish Secretary, was promptly promoted to Defence Secretary – Malcolm Rifkind going to Scotland – and Cabinet resumed where it had been so rudely interrupted

So what was it all about? Did the flamboyant Heseltine spontaneously combust with frustration? Did he calculate that Thatcher was so weak – or could be so weakened after the "leak"– that she could be toppled just when the economy was coming right? Or, with an eye to the future, was he seeking martyrdom on the cross of Europe by an overbearing PM who "denied free discussion"?

These are nice questions. Tarzan, as he was called, is more complex than he looks. He cannot evade the charge of premeditation because he managed to cobble together a 20-minute 2,500-word press statement soon after his resignation. And who was instrumental eventually in bringing Thatcher down? Why, Heseltine at the prompting of another Eurofanatic, Sir Geoffrey Howe. And what was then the issue? Why, Europe – just like the Westland affair.

Cameron beware, lumbered as you are with a mainly Eurosceptic Conservative Party and Europhile Liberal Democrats. Europe haunted Thatcher and Major and tore at New Labour. It will try to sink its teeth into you, too. It dogs all governments.