Mr Khan will attend a special ceremony at 04.45 on Sunday, the exact time German battleships fired on a Polish Garrison at Westerplatte, the first act of WWII.

Ahead of travelling tomorrow the Labour Mayor said he will use the trip to highlight "London will always be a welcoming home" for the close to 200,000 Polish nationals who live in the capital.

Mr Khan, said: “I am looking forward to visiting Poland to bang the drum for London and to spread the message that, however Brexit turns out, London will always be open for business, trade and talent and a welcoming home for Polish citizens.

"With far-right extremism on the rise on a scale we have not seen for decades, I will be using this visit to make the positive case for tolerance and inclusion in London, Poland and across Europe."

Mr Khan will also lay a wreath at the Monument to the Ghetto Heroes in Warsaw before taking part in a debate at the Museum of the History of Polish Jews.

The Mayor of Gda?sk, Aleksandra Dulkiewicz, said:"I am delighted that during the ceremony to commemorate the 80th anniversary of the outbreak of World War Two, Gda?sk will host the Mayor of London."

The Mayor of Warsaw, Rafa? Trzaskowski, said: "Our cities need to stand together, to share our experiences and best practices, finding innovative solutions to improve the quality of citizens' life."