The first of five badly-wounded Ukrainian soldiers has arrived in Birmingham for UK-funded medical treatment, the Foreign Office said.
Specialist staff at the Queen Elizabeth Hospital are performing reconstruction surgery for severe wounds sustained in the battle against pro-Russian rebels.
Another is due to be flown in next month to the facility, which in recent years has been the main centre for treating UK soldiers badly injured in Afghanistan.
A surgical team is due to travel to Ukraine next month to assess up to three others who could benefit from British help.
The move is part of a wider initiative by Kiev's allies, including Germany, Poland and Canada, with the as-yet unspecified cost being met by the Foreign Office, the Ministry of Defence and the Department for International Development from a joint conflict fund.
Foreign Secretary Philip Hammond said: "The UK stands squarely behind the Ukrainian people and government as they defend their nation's independence and work towards the political, economic and governance reforms that are vital to rebuilding the country.
"The surgical unit at Queen Elizabeth Hospital has extensive experience and skill in treating battlefield injuries and I am pleased that we can use that expertise to rebuild the lives of those who have been severely wounded in the conflict in eastern Ukraine."
On Friday, Ukraine's president Petro Poroshenko hailed the first day since the conflict erupted months ago when none of his country's soldiers were killed or wounded, as a fragile ceasefire appeared to be holding.
A ceasefire was agreed in September but has been widely breached and the death toll has since passed 4,300.