Since Ukraine gained independence in 1991, security co-operation with the UK has been key.
With aspirations to join both the EU and NATO, initial military assistance to Ukraine was focused on defence reform, planning and building.
In 2014, in response to Russia's annexation of Crimea and the crisis in Eastern Ukraine, allies significantly stepped up their support – at the request of the Ukrainian government.
A year later, the UK launched Operation Orbital, a non-lethal training and capacity-building operation for the Ukrainian armed forces.
In contrast to the US, the UK ruled out providing lethal arms to Ukraine at the time – with Germany and France also opposing the arming of Ukraine at the time.
In 2020, the Ministry of Defence (MOD) announced the UK will lead a multinational maritime training initiative to boost Ukraine's Navy.
Watch: Defence Secretary confirms 'light anti-armour defensive weapons' for Ukraine amid Russia tensions.
The UK and Ukraine launched the Naval Capabilities Enhancement Programme to develop Ukraine's naval capabilities.
This included Ukraine purchasing two Royal Navy Sandown-class minehunters, help in building new naval bases in the Black Sea and Azov Sea and the development and joint production of eight missile warships.
To date, more than 21,000 Ukrainian military personnel have trained under the initiatives.
UK's support to Ukraine this year
As tensions between Russia and Ukraine heightened in early 2022, in January the Defence Secretary confirmed the UK would provide "self-defence" weapons to Ukraine.
Under Op Orbital, British personnel provide initial training on how to use the systems.
In an exclusive interview with Forces News, Chief of the Defence Staff, Admiral Sir Tony Radakin, said 200 Ukrainian soldiers will arrive in the UK every day from the week commencing 27 June 2022, to receive training from the British Armed Forces as the conflict with Russia continues.
Watch: CDS reveals 200 Ukrainian soldiers will arrive every day for training.
In April, Armed Forces Minister James Heappey announced "a few hundred" Ukrainian troops will be trained in Britain on how to use the armoured vehicles being provided to the country by the UK.
Before the Russian invasion, the Armed Forces Minister said British troops were being sent to Ukraine to help with training on the anti-tank missiles supplied by Britain.
However, he remarked all the British troops would be "withdrawn" should a conflict begin.
What military equipment has the UK sent Ukraine?
On 6 June, the UK announced it would donate three M270 MLRS launchers with GMLRS munitions to Ukraine.
The M270 multiple-launch rocket system is among the most potent weapons used by the British Army and it can unleash all of its 12 rockets in less than a minute.
The MOD has also sent Ukraine the following pieces of military kit:
- More than 5,000 Next-generation Light Anti-tank Weapon (NLAW) missiles.
- More than 200 Javelin anti-tank missiles.
- 120 armoured vehicles.
- 1,360 anti-structure munitions.
- Stormer vehicles fitted with launchers for anti-air missiles.
- New anti-ship missile systems.
- More than 400,000 rounds of small-arms munitions.
- 4.5 tonnes of plastic explosives.
- More than 200,000 pieces of non-lethal aid such as helmets, body armour and medical equipment.
- Electronic warfare equipment, including GPS jammers, counter-battery radar systems and night vision equipment.
- Dozens of heavy-lift UAV systems.
WATCH: How can British multiple-launch rocket systems help Ukraine?
What other countries are helping Ukraine?
Military assistance for Ukraine – both in 2014 and in 2022 – has not come only from the UK.
Since 2014, the US has provided Ukraine with more than $2.5bn in security assistance – including military training and equipment.
The Obama administration provided significant non-lethal military equipment to Ukraine, supplemented over the course of 2015 with a package of military assistance worth $75m that included Humvees, surveillance drones, night vision devices and military ambulances.
Under the Trump administration, the US started supplying Ukraine with lethal weaponry such as Javelin anti-tank missiles, as well as sniper rifles, rocket-propelled grenade launchers and two retired US coast guard patrol boats.
In March 2021, the US Department of Defense announced a further $125m military assistance package to Ukraine, which was followed up with further packages in June and September 2021.
Since the start of the war in 2022, the Biden administration has sent a number of military pieces of equipment and weapons to Ukraine.
In June, President Biden announced the US would send a small number of high-tech, medium-range rocket systems part of a $700m (£553m) portion of security assistance for Ukraine from the US that will include helicopters, Javelin anti-tank weapon systems, tactical vehicles and spare parts.
On 23 June, the US Department of Defense also announced new funding to help in the war against Russia, bringing the total amount spent by the US on Ukraine's security needs to $6.5bn (£5.3m) since President Biden entered the White House in January 2021.
Similarly, Germany also committed to providing MLRS and Guided MLRS rockets to Ukraine.
NATO also has an assistance package in place with Ukraine, promoting defence reform through capacity building and development programmes.