The head of the British Army has told the military that "Ukraine needs our tanks and guns now" but acknowledged it will leave the Army "temporarily weaker".
In a message to military personnel seen by Forces News, General Sir Patrick Sanders said there is no better use for the tanks and guns being sent but said there is "no denying" it will leave the Army weaker.
The Chief of the General Staff said on an internal military platform that the decision to help the Ukrainian military defeat Vladimir Putin's invasion would make the UK safer.
General Sir Patrick's statement comes after Defence Secretary Ben Wallace announced the "most significant package of combat power to date to accelerate Ukrainian success".
"Wars are won and lost on land," the Chief of the General Staff (CGS) said in his statement seen by Forces News.
'Ukraine needs our tanks and guns now'
The British Army chief added: "The Ukrainian army needs more weapons and equipment if it is to maintain the momentum.
"Ukraine needs our tanks and guns now. I know they will put them to good use. And there can be no better cause."
The service chief also stressed the "vital" need to restore his Army's warfighting capability, acknowledging the impact on the British Army.
"There is no doubt that our choice will impact on our ability to mobilise the Army against the acute and enduring threat Russia presents and meet our Nato obligations.
"Our tank crews and gunners will feel the impact the most, but the decision also brings the opportunity to accelerate the modernisation and transformation of the Army ahead of Russia," the CGS said.
He has promised to accelerate the replacement of AS90 – the self-propelled artillery guns Prime Minister Rishi Sunak announced that would be sent to Ukraine to help the country fight against Russia's invasion.
In his statement, General Sir Patrick said: "So we will accelerate the replacement of AS90, bringing it into service from 2027 along with fielding long-range precision fires and hypersonics. In the immediate term, we will look at how we can temporarily fill the gap in our armoury.
"And the arrival of Challenger 3 means our armoured regiments will field one of the most capable tanks in the world – packing a much greater punch and with better protection."
Mr Sunak hopes the UK's intensifying support will increase the pressure on Russian President Vladimir Putin and galvanise support among Western allies.
He signed off on sending 14 British Army Challenger 2 main battle tanks to Kyiv, as well as around 30 AS90 self-propelled guns during a call with Ukrainian leader Volodymyr Zelensky over the weekend.