The International Criminal Court prosecutor has released a statement inviting a State Party (eg UK) to to refer the situation in Ukraine to the ICC and his office, which would allow the ICC to actively and immediately proceed with the ICC prosecution office's independent and objective investigations into the events unfolding in Ukraine.

https://www.icc-cpi.int/Pages/item.aspx?name=20220228-prosecutor-statement-ukraine

Because Ukraine is not a State Party it can not refer the situation to the ICC and so in order to avoid legal challenges over whether Ukraine were/are able to accept the International Criminal Court's jurisdiction over alleged crimes under the Rome Statute occurring in Ukraine territory, I want the UK to to refer the situation in Ukraine to the ICC.