Petro Poroshenko is to be sworn in as president of Ukraine, after his victory in the May 25 poll.
Yesterday, he met with Russian President Putin briefly at D-Day commemorations, saying it could be the start of dialogue between the countries.
More top news
Two private citizens have already paid a "significant deposit" to take the week-long trip.
Slippy start tomorrow with frost & ice
The court will determine how much the UK government and travel firms knew about the risk of an attack on tourists holidaying in the area.