Michel Barnier is a busy man these days. The Brexit endgame probably allows him little time for reading.

Nevertheless, I would recommend that, as he seeks to negotiate with a UK government behaving in an increasingly irrational way, by insisting that “no deal” is on the table, he should at least dip into the “madman theory” of negotiation.

Richard Nixon’s administration, in its approach to the Soviet Union and others, was a proponent of the “madman theory”. Nixon’s reported strategy was to put it about that he was volatile and irrational.

This would in turn, the theory went, make hostile leaders bend to his will since they would be afraid of provoking him.

The “madman theory” is having a profound impact on unfolding events

The proximity of Nixon’s finger to the nuclear button was a crucial ingredient in the strategy.

The “madman theory”, of course, did not begin or end with Nixon. Machiavelli argued that sometimes it is “a very wise thing to simulate madness”.

More recently, Donald Trump’s approach to North Korea, and to arms control generally, bears hallmarks of the strategy.

Brexit clock

As the Brexit clock runs down, the time for pussyfooting around has passed. Most people must now take it as a given that Jacob Rees-Mogg and his cohorts are stone-cold crazy.

The urgent question which should now be asked is whether Theresa May herself, although sane, has built the “madman theory” into her negotiating strategy.

BREXIT: The Facts Read them here

To put it another way, is the British bulldog showing symptoms of the rabid tail that has been wagging it?

The “crazy guy” strategy, as it is sometimes called, is of little value in the UK’s negotiating approach towards the EU. The major flaw is that the “no deal” button over which May’s finger now deliberately hovers would, if triggered, rain down its destruction principally not on the EU-27 but on the UK itself.

For the EU to give any credence to the threat of volatility and irrationality, it would have to believe that the UK government is not only completely mad but also colossally stupid.

May can’t get the EU to play chicken; the game only works if your opponent shares your fear

Central UK threat

There would, it is true, be some fallout beyond Britain’s shores from a no-deal Brexit.

But the central UK threat is that, if it doesn’t get its way, it will punish itself. The EU naturally hasn’t the slightest intention of undermining the insurance policy for the Belfast Agreement which was painstakingly negotiated with the full input of the UK government.

The EU may be willing to provide further reassurances about what the withdrawal agreement means but, even on that, they are conscious that nothing will satisfy Mogg’s European Research Group pipers who have been calling the tune.

Nevertheless, elsewhere the “madman theory” is having a profound impact on unfolding events.

The threat of the UK crashing out of the EU is a vitally important weapon on the second front in May’s war, namely her campaign to compel a majority in the House of Commons to support her deal.

Most MPs, including many of those who voted for Brexit, care deeply about their rightly beloved country, not to mention the voters in their much-beloved constituencies.

They understand well the havoc a no-deal Brexit would wreak on Britain.

They probably also get it that the implied threat of mutually assured destruction, a policy captured perfectly by its popular acronym, MAD, would in this case be MUSH: Mad Unnecessary Self-Harm.

Immense damage

However, where the “madman theory” comes into the parliamentary calculations is not the assessment that May, in the privacy of her own mind, would consider inflicting the immense damage of a “no-deal” Brexit on her country.

Rather , it is brought into play by the not unreasonable fear among many MPs that the clock will be run down so far, the atmosphere so febrile, the tabloid press so irresponsible, the parliamentary procedures so complex and the lunatic minority so loud of voice, that a combination of confusion, incompetence and the unpredictability of the battlefield, rather than deliberate government policy, could lead to national catastrophe.

The “madman theory” does not wash with Brussels. However, it continues to shape the debate at Westminster.

May can’t get the EU to play chicken; the game only works if your opponent shares your fear. In parliament, however, chicken is now pretty well the only game in town.

Bobby McDonagh is a former Irish ambassador to the EU, Britain and Italy