Russia seized key Parliamentary and Police buildings from the Ukrainian authorities and then ran a sham referendum in an attempt to legitimise its actions.

Once President Putin signed an illegal decree to absorb Crimea into Russia, the Russian authorities ran illegitimate ‘elections’ and imposed Russian citizenship, Russian law and military conscription on everyone living in this part of Ukraine.

Foreign Secretary Jeremy Hunt said:

I condemn the illegal annexation of the Autonomous Republic of Crimea and the city of Sevastopol, Ukraine, five years ago. The UK will never recognise Russia’s illegal annexation of Crimea and we call on Russia to end their illegitimate control of the peninsula and their attempts to redraw the boundaries of Europe. Russia’s pattern of unacceptable behaviour has continued with their supply of weapons and personnel to the conflict it initiated in eastern Ukraine, the illegal construction of a bridge connecting mainland Russia with Crimea, and their relentless attempts to monopolise the Kerch Strait in a campaign intended to undermine Ukraine’s economy and demoralise its citizens.

Russia continues to commit human rights violations beyond its borders by systematically persecuting those who voice their opposition to the illegal annexation of Crimea. I call for the immediate release of all Ukrainian political prisoners, who are being held in Crimea and Russia without access to international monitoring organisations or essential medical treatment. Russia must also immediately release the 24 Ukrainian servicemen, who were detained whilst lawfully attempting to sail through the Kerch Strait.

We join NATO and the EU in condemning Russia’s unjustified use of force on Ukrainian vessels in November last year. The UK, along with our EU and G7 partners, remains unwavering in our support for Ukraine’s sovereignty and territorial integrity. Crimea is Ukraine."

https://www.gov.uk/government/news/foreign-secretary-statement-on-the-fifth-anniversary-of-the-illegal-annexation-of-crimea