Why does Sir Keir Starmer want to be Prime Minister? It's very hard to know. But what's certain is that Britain is paying the price of having a PM with no interest in doing the job.

Perhaps you think 'all politicians are liars'. Yet the disgraceful appointment of Peter Mandelson points not just to dishonesty, but to a premier too idle to ask basic questions and too weak to face the answers.

I have spent hours across the despatch box watching how Starmer operates. He doesn't just refuse to answer questions, he cannot answer questions. He doesn't know how to respond because he's not prepared to do the work.

Despite seven months of scandal at the very heart of government, Starmer claims to have made no enquiries, to have seen no documents, or to have heard anything that would have told him Peter Mandelson failed the security vetting.

Even by his own defence (fanciful as it is), Starmer has shown himself lacking in any grip, to be lazy in his thinking and, as it turns out, too idle to ask the most basic questions of his staff.

The hypocrisy is everywhere. A year ago, Starmer said 'defence would be the first thought in the morning, the last at night'. Yet the authors of his own Strategic Defence Review are lining up to criticise his dangerous inaction on defence spending.

The debacle over the Iran war has exposed a Government that continues to prioritise welfare payments over defending our country, even as three former Labour defence secretaries beg Starmer to increase spending on our national security and cut the ballooning benefits budget.

And at the heart of it is the Prime Minister's vision-free leadership. In this Labour Government, ministers pull in different directions. Policies are announced without clarity and abandoned when reality intrudes. The result is an administration grinding to a halt.

Curiosity is what drives serious leadership. It is what makes a prime minister read the extra briefing and challenge the easy assumption. Without curiosity, problems are neither fully understood nor solved.

Without it, there are no real ideas. In its place, political emptiness: A polished exterior, but with no substance behind it. There's an impression of seriousness, but when you look for the underlying vision, it's just not there.

Compared with recent shambolic Labour leaders such as Ed Miliband and Jeremy Corbyn, it's fair to say that Starmer looks the part, at least. The expensive glasses, the suit and tie give the right impression. But compare Starmer to real leaders, the sort who show conviction and strategic clarity, and the gap is obvious.

In fact, the real scandal is not the appointment of Mandelson – serious though that is – but the woeful direction of our country under Starmer's incurious regime.

Keir Starmer claims to be furious with officials. It is us who should be furious with him because hard-working Mail on Sunday readers are paying the price for his mistakes.

A real leader stands up for the country, puts the national interest first and takes the hits. Yet this scandal exposes a man who thinks only about himself. Starmer has sacrificed his staff, blamed the security services and sent ministers out to lie on his behalf.

He is disloyal not just to his country, but to those serving beneath him. People can accept a leader who makes an unpopular call and stands by it; they loathe a leader who lets others take the fall while he clings on. Time and again, when things go wrong, it is always someone else's fault. Starmer's stock defence is 'don't blame me, I'm only the Prime Minister'.

The hypocrisy is staggering. The Labour leader built his reputation on standards, rules, and truthfulness in public life. Yet the voters know that those rules – sacred for the rest of us – are optional when it comes to the powerful. This is dishonesty mingled with weakness, evasion and contempt.

Authority does not just come from the title of Prime Minister. It is earned through the truthfulness and responsibility that Starmer lacks.

He is either lying about what he knew about Mandelson's appointment, in which case he is corrupting the office, or he is so lazy and incompetent that he is unfit to run the country.

We are entering a harsher world which is less stable abroad, less cohesive at home and less certain of itself overall.

Questions about growth, security, immigration, integration, family, identity and national purpose are not abstract debates. They will shape the country our children inherit, the opportunities they have, the values they grow up with, and whether they feel they belong to a nation that knows who it is and where it is going.

Economic stagnation, failing public services, the rising cost of living, declining living standards, uncontrolled migration and a of lack integration, threats from Russia, China and Iran... These are not abstract problems, they shape both our daily lives and the future our children will inherit.

Yet we have a Prime Minister consumed by his own survival. And, while he hangs on, desperately, the country drifts. While he protects himself, decisions are delayed and problems fester.

Starmer has no idea how to make this country better, which is why we are becoming a nation that simply manages decline instead of striving for greatness. It is not a future I will accept – and it is not the future this country deserves.

This is not a moment for bland managerialism, or for leaders clinging to office while the country loses confidence.

It is a moment for seriousness, for courage, and for a government with a clear sense of duty to the next generation.

Starmer has misled Parliament over Mandelson, misled the country and is taking the public for fools. This is not just a political failure. It is a moral one: He has put our national security at risk, he has lost the right to govern, he should resign.

Britain can meet the many challenges it faces, but only if we are honest about them. And only if – like the Conservative Party under my leadership – we have a clear vision for the country and a clear plan to deliver it.