Ukrainian President Volodymyr Zelensky is visiting the UK for the first time since Russia's invasion of Ukraine.
He is meeting with UK Prime Minister Rishi Sunak and King Charles, and is set to give a speech to Parliament.
The UK has expanded its training of Ukrainian forces to cover fighter jet pilots and marines, as well as announcing a new round of sanctions targeting Russia, including IT companies and military equipment manufacturers.
The UK is also sending Challenger 2 tanks and offering training in how to operate them, with plans to train Ukrainian pilots to fly NATO-standard fighter jets.
The UK has spent £2.3bn on military assistance for Ukraine and has taken over 100,000 Ukrainian refugees.
Zelensky is expected to address the European Parliament on Thursday before attending a summit of EU leaders.