The total includes "generous" donations from The Queen, the Prince of Wales and the Duke of Cambridge, as well as hundreds of thousands of members of the public.

The Ukraine appeal was launched on Thursday by the Disasters Emergency Committee (DEC), which brings together 15 leading UK aid charities at times of crisis overseas.

It is feared that up to four million people could flee the country because of the Russian invasion, many in desperate need of food, water, medical assistance and protection.

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DEC chief executive Saleh Saeed said: "We are extremely grateful for the huge generosity of everyone in the UK who has donated to the DEC Appeal.

"We are also very grateful for the generous support of the Royal Family.

"While we have raised an astonishing amount in the first day of the appeal, we urge people to continue donating as the need is great and the response needed is likely to run into months and years. Please help now."

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The £55m total includes £20m donated by the government as part of its UK Aid Match scheme after Prime Minister Boris Johnson promised that every pound donated by the British public would be matched by the government - up to the value of £20m.

The Welsh government will provide £4m through the appeal, with First Minister Mark Drakeford telling Sky News he hopes his country can be a "nation of sanctuary" for those fleeing Ukraine.

Game Of Thrones star Kit Harington, who voiced a TV broadcast publicising the appeal, said: "Thousands of people in Ukraine have fled their homes to escape conflict - leaving behind loved ones, homes, and jobs.

"These people urgently need shelter, food, and water. With your help, DEC charities can help families affected by this crisis. Please donate now at dec.org.uk."

Elsewhere, the World Health Organization Foundation has launched an international health appeal with a target of $57.5m (£43.2m) needed to deliver urgent healthcare to those in Ukraine as well as refugees.