People's expectations of their politicians may be lower than we would like, but surely our ministers should be broadly competent, intelligent and informed, and have a certain regard for facts on which to base opinion.

So what are we to make of the contribution of defence minister Penny Mordaunt on national television yesterday (22 May) when she confidently rejected the proposition that all EU countries have a right of veto over new entries such as Turkey? I have watched back the relevant clips and, without being inside her mind (a place I have absolutely no desire to be), it is not possible to know for sure whether she is plain stupid or a liar or both. But at a time when security is such a big issue, and the UK still (at least until June 23) a major power, I do not really think we should have as armed forces minister someone who is either stupid or a liar.

According to the screaming headline on the pile of Metro papers at the bottom of the escalator at Bond Street station this morning, the prime minister prefers to see his minister as a liar rather than just stupid. 'Cameron's fury over minister's "lies" on Turkey', it says. Good for him, I thought. It is about time he called out the lying tactics of the Leave campaign for what they are.

But when I picked up a Metro and read the article, I saw what he actually said was that his minister's statement on the Marr programme was 'misleading' and 'absolutely wrong'. He then added that Turkey's entry to the EU is unlikely until the turn of the next century, if at all. His comments were pretty mild given the scale of the stupidity/lying involved.

So how can he be the leader of a government that has that position on an important foreign policy issue, and houses a minister in a significant foreign policy department who goes on TV and says something that is so far removed from his viewpoint? And how can she survive if she is either a proven liar or totally incompetent to the point of not knowing something that any politician alive ought to know about how EU enlargement works?

The answer comes in two parts. The first is that Cameron has taken a decision that if his party is to recover and reunite post the June 23 referendum, then he should seek to minimise so-called 'blue on blue' attacks of Tory on Tory. The problem with this is that half of that particular genie is out of the bottle, as the Leave side of the Tory party is showing no such restraint.

After Boris Johnson has called the arguments of the man who leads his party 'demented' and suggested the chancellor lacks principle, and Iain Duncan-Smith has indicated his very strong view that neither of them are capable of telling the truth, then Cameron and George Osborne are frankly being naive if they think they can just sit there and take these attacks without dismantling the arguments and the personalities behind them.

There has been in recent days a hint of, at best, borderline racism in the way Leave have sought to use this issue. The bad news is its unpleasantness and irresponsibility. The good news is it suggests Leave are reading the same polls as I am, which show they are losing the economic argument, and need to shift goalposts.

Boris Johnson has a long history of making 'misleading' and 'absolutely wrong' statements, not least when he was the Daily Telegraph's Brussels correspondent, peddling fiction about the things 'Europe' intended to do to Britain. The Johnson habit lives on, such as last week when he claimed 'Europe' prevented us Brits from buying or selling bananas in bunches larger than two or three. Misleading. Absolutely wrong. A lie. Trivial on one level. But the issue is less trivial when the Leave campaign deliberately peddles lies, ventilated by the Brexit Lie Machine of our largest selling newspapers, that millions of Turks are heading our way not for last weekend's friendly football match against England but seemingly to 'take our jobs, abuse our welfare and clog up our schools and roads and hospitals,' as a BNP member might put it.

It was particularly disappointing to see that it was Michael Gove, one of the more intelligent members of the Leave team, leading the charge on this. "Because we cannot control our borders — and because our deal sadly does nothing to change this fact — public services such as the NHS will face an unquantifiable strain as millions more become EU citizens and have the right to move to the UK," he wrote in The Times.

There has been in recent days a hint of, at best, borderline racism in the way Leave has sought to use this issue. The bad news is its unpleasantness and irresponsibility. The good news is it suggests Leave are reading the same polls as I am, which show they are losing the economic argument, and need to shift goalposts.

If Mordaunt has revealed herself as being unfit for a serious government job, so has Johnson

Cameron is right that the Tory Party will have some healing to do on 24 June. But if Mordaunt has revealed herself as being unfit for a serious government job, so has Johnson. When Johnson attacked Barack Obama during the US president's visit to the UK, in terms that again appeared to show the racist streak running through him, Cameron should have come out and condemned him in the strongest possible terms. I understand his reluctance to do so. Partly because of the blue on blue thing. But also because he knows Johnson has an appeal in the Tory party, and poses a real threat to Cameron's preferred successor, Osborne, so he needs to be careful not to make him even more popular by turning him into a martyr.

Symbolically, Johnson is currently touring the country on a bus that manages to have three lies emblazoned upon it. A lie about the financial cost of our EU membership. A lie that this is money that could be spent on the NHS (and if anyone seriously believes Leave leaders care about the NHS they don't know them well enough). And a lie about the claim that the UK does not control its own destiny.

In refusing properly to engage with a Leave side that thinks it can say what it likes, and by accepting Johnson and cohorts can do as they please without real consequence, then the thing Cameron and Osborne are united in wanting to avoid – a Johnson succession – becomes likelier. They are ventilating his credibility when they should frankly be destroying it, given the ammunition he is providing.

In refusing properly to engage with a Leave side which thinks it can say what it likes, and by accepting Johnson and Co can do as they please without real consequence, then the thing Cameron and Osborne are united in wanting to avoid - a Johnson succession - becomes likelier

We know that Johnson, for whom principles are tradable, has failed to deny (perhaps because his editors know the truth) that he had two columns prepared for The Telegraph, one for Remain, one for Leave, and opted for the latter on the grounds it was a better bet for his route to the top job. He is betting that if Remain wins, Cameron will feel he has to reward Johnson with a big job, because of his appeal in the party, and to show he is determined to reunify. If Leave wins, Cameron is a goner and Johnson thinks he is home and dry. So he has the PM over a barrel. Cameron needs to show he is not prepared to be treated with such contempt.

The second part of the answer (with apologies for it being so far down from the first) is that virtually every Tory MP believes they have the next election in the bag, regardless of what happens on 23 June. The reason for their confidence – or arrogance, or complacency, call it what you will – is that they do not think the country is ever going to put Jeremy Corbyn or John McDonnell in power. This is a dangerous mindset for a not terribly popular governing party to have. Added to which you just need to look around the world to see very strange things happening. Donald Trump. Bernie Sanders. Neo Nazis in Austria. Crazy stuff in the Philippines. I am not comparing these people with Corbyn, simply saying we live in volatile and unpredictable times.

That is why Remain must resist complacency, whatever the polls may say. It is also why the Tories should curb their tendency to believe they have a divine right to rule. If Johnson does become their leader the chances are we will be having an election sooner than we might think. The story of the police getting involved in what looks to me like serious breaches of campaign rules during the General Election seems to me like one of the most under-reported stories of our times. Watch out for it.

It all means that unless Johnson is brought down to the level the nature of his current campaign deserves to place him, then the next election could be fought between a Labour leader most Tories and many others consider to be unelectable as PM but unassailable as leader, and a Tory leader of whom many non-Tories – myself included – would put in the same boat. Then, frankly, anything could happen.

Alastair Campbell is a British journalist, broadcaster, political aide and author, best known for his work as Director of Communications and Strategy for Prime Minister Tony Blair between 1997 and 2003. He is the author of two books on mental health and is an ambassador for Time to Change.