Within a few hours last week, the two most senior ministers responsible for the defence of the nation resigned.

Their charges amounted to a broadside on the Government's ability to fulfil its most important duty: the Prime Minister was unable, and his Chancellor unwilling, to commit the resources necessary to keep the country safe.

Having wrestled with the system and seen the mismatch between what the Government says about defence and what it will pay for, John Healey and Al Carns concluded resignation was the only option.

Too often such resignations are the manoeuvres of those playing politics. I suspect not this time. It would be foolish not to heed their warnings. 

Today, Britain is more imperilled than any time since I first put on a uniform more than half a century ago.

Our own intelligence indicates a Russian attack on Nato is plausible by 2030. We cannot stand on the sidelines any longer, nor take our security or freedom for granted.

It is more than a year since the Strategic Defence Review was published. Since then we have lost time we did not have, credibility in the eyes of our allies and foes, and the confidence of the brave men and women who serve this country.

The Ministry of Defence needs £28billion in the next four years to meet costs. 

The £13.5billion reportedly on offer in the Defence Investment Plan is the hollow legacy of a PM unable to impose authority in his own Government. 

And behind every programme cut or saving identified are those in uniform being asked to do more with less. 

What our forces do is remarkable nonetheless. Look at the interception of the Russian shadow fleet vessel, or the recent life-saving medical-care operation on Tristan da Cunha. 

These campaigns demonstrated capabilities that very few nations can match. But it is wrong to think reach rests solely on military strength. International development and diplomacy are just as crucial.

Failing to invest sufficiently in these two key components of Britain's soft power, one of the few domains in which we remain world-leading, fuels instability, allows threats to proliferate and cedes influence to our adversaries. They remind our friends we still care – and our enemies we can still reach them.

The ongoing Ebola outbreak is a troubling example. The 2014 epidemic was met by more than 1,500 British military personnel building treatment centres, training thousands of workers and turning jungle into healthcare facilities. The civilian response was no less emphatic. By 2016 Sierra Leone was Ebola-free.

But today's outbreak in the Democratic Republic of Congo and Uganda has been dogged by inadequate preparation. Our own development minister admits aid cuts left us under-prepared.

Where before our Armed Forces and humanitarians worked hand-in-hand to contain crises, now we lack the means to do so. 

Meeting today's challenges requires a coherent national security strategy: properly funded, well-communicated and delivered through decisive leadership.

Next week is Armed Forces Week, and the nation will honour those who serve or have served. 

Our gratitude is important, but it is no substitute for the resources that enable those brave men and women to keep us safe.

The first responsibility of any government is the defence of the realm. The two ministers who were responsible have just told us the Government is failing in that fundamental duty. We should take them at their word.

General The Lord Dannatt was Chief of the General Staff from 2006 to 2009.