“We need to be prepared Putin will face a “huge cost” if other countries are threaten”

First Sea Lord, Admiral Sir Ben Key Ben accused Putin of an “egregious wrong” against Ukraine, urging the UK to continue to support Volodymyr Zelensky, the Ukrainian president, to help provide his fighters with “the wherewithal to defend their territory, their homeland and their people”.

Vladimir Putin will face a “huge cost” if he dares encroach on any nations outside Ukraine, the head of the Royal Navy has said. 

In his first interview as First Sea Lord, Admiral Sir Ben Key told The Telegraph it was imperative that Nato nations worked to “contain” the invasion of Ukraine and did not allow it to “accelerate away from us”. 

“The lessons of history would say that we are in a particularly fragile moment right now, which is why it’s really important that whilst the support we are giving to Ukraine at the moment is to enable them, we have to show in robust and resilient posture across the rest of the contact line with Russia ... so that President Putin understands this is not something that he can broaden without huge cost to him and Russia.” 

Admiral Sir Ben said while the hope was that Putin “chooses to desist”, that outcome feels “a long way away at the moment”. 

Sir Ben said that although the war in Ukraine is mostly land-based, Nato navies needed to maintain a deterrent posture to “counter Putin’s actions and dissuade him from doing more”. 

“We represent a threat,” he said. “The Russians effectively tried to exclude any other any other ships from operating in the northern part of the Black Sea and the Ukrainians demonstrated that that was not something that they could do freely.”

He said “ships become valid targets” in war, and the UK needed to ensure it was prepared for that eventuality. “That requires for our posture to be correct, for our capabilities to be properly aligned, for us to be modernising and adapting to seeing what others can do and what technology opportunity offers us,” he added.

Sir Ben revealed that he had spoken to Amiral Pierre Vandier, his French counterpart, about The Telegraph’s recent disclosure that British officials suspected Exocet missiles used in the Falklands war contained a “kill switch” that could disable them but France denied such a device had been inserted into the weapons. 

“When I was speaking to my French opposite number about it, his single comment to me was ‘if we found this kill switch could we let him know, because it would be quite helpful for him to know about’,” Sir Ben said. 

Falklands veterans have joined calls for an inquiry into the allegations that France withheld secrets about the weapon. Sir Ben said that while there has been “no evidence made available to us of this capability”, he would not stand in the way of an inquiry.

As the former Chief of Joint Operations, he oversaw numerous missions around the world including Operation Pitting, in which 15,000 people were evacuated from Kabul. Insiders believed the success secured his promotion to head of the Navy.

Sir Ben, who also held the position of Fleet Commander, joined the Navy as a university cadet and went on to qualify as both helicopter aircrew and as a principal warfare officer. He has seen service around the world in a variety of frigates and destroyers. 

Closer to home, he has pledged to work on issues such as gender inequality and vowed to take on “toxic” leaders to help women in the force. He acknowledged that, despite some progress, there remained a long way to go until gender parity was achieved. 

“We’ve still got a lot of work to do – the day we think we’ve cracked it is the day that we fall massively behind,” he said. 

Sir Ben said that while he felt “excited by the prospects” for the Navy’s future, he could not yet confidently say it had learnt how to treat men and women equally. 

“Have we solved that everybody who comes to work in the Royal Navy brings out their best and is recognised for that, rewarded and applauded for that and feels comfortable in an environment? Have we got that right for everybody at the moment? No,” he said. 

Sir Ben’s comments followed the recent publication of a damning report by the Commons defence select committee which resulted in his predecessor, Admiral Sir Tony Radakin, now the Chief of the Defence Staff, admitting that the military had failed to value servicewomen.