The UK will also provide £2.5bn in military aid to Ukraine in 2024-25, an increase of £200m on the previous two years, Sky News reports.
About £200m will also be spent on a push to procure and produce thousands of military drones.
The UK package will be the largest delivery of drones to Ukraine from any nation, according to Downing Street. Most are expected to be manufactured in the UK.
According to British Prime Minister Rishi Sunak, who made a surprise visit to Ukraine today, it will also provide the country with long-range missiles, air defence, artillery ammunition and maritime security.