European leaders, including Germany’s Angela Merkel, will mark the 80th anniversary of the start of the second world war in Warsaw on Sunday. But Donald Trump – who cancelled on his Polish hosts at the last-minute last week, citing concerns over a hurricane barrelling towards Florida – was due to spend the day at his golf club in Virginia.

The conflict began in the early hours of 1 September 1939, when a Nazi battleship attacked a garrison of Polish soldiers at Westerplatte. Poland’s government had moved this year’s commemorations from Westerplatte, near the Baltic port city of Gdańsk, to Warsaw, in anticipation of a visit from the US president, who was to give the keynote speech. But Trump cancelled, citing Hurricane Dorian , and sent vice-president Mike Pence in his stead.

Shortly after Trump cancelled, Merkel made a last-minute announcement that she would attend. Yesterday it emerged that Trump, who had given the impression he would spend the day at Camp David with experts to monitor Dorian’s progress, had in fact flown by helicopter from Camp David to his Virginia golf club. He is expected to return to Washington on Sunday to attend a briefing at the Federal Emergency Management Agency (Fema).

Those attending in Warsaw will include the foreign secretary, Dominic Raab, at the head of a British delegation, while London mayor Sadiq Khan will mark the anniversary in Gdańsk, where the liberal-led city authorities are hosting their own events.

On 3 September, two days after the attack on Westerplatte and following a Nazi assault on other parts of Poland, British prime minister Neville Chamberlain made his famous radio declaration that “this country is now at war with Germany”. Despite this, little practical assistance was given to Poland, which was crushed within weeks by the Nazis and invaded by the Soviet Union from the east, according to a pact signed by Adolf Hitler and Joseph Stalin in August 1939 that contained a secret protocol by which the two powers would divide Europe.

Ten years ago in Westerplatte, the Russian president, Vladimir Putin, called the treaty a “mistake”, but a recent Russian campaign has sought to rehabilitate the controversial treaty. It has been met with outrage in Poland and elsewhere in central Europe and is one of the reasons why Putin was not invited to Warsaw this year.

Poland’s government, ruled by the nationalist Law and Justice (PiS) party, believes other countries do not appreciate the level of Poland’s suffering during the war, but has been accused in recent years of rewriting history by emphasising heroism at the expense of darker pages. The government also wants Germany to pay reparations for war damage, an issue the current German government insists is not on the table. A parliamentary commission is currently working on drawing up an estimate of the amount to be demanded from Berlin, though the issue is unlikely to be raised during the commemoration.

Poland’s government has been at loggerheads with the EU over rule of law issues, but has been praised by Trump, and there was hope that his visit would give them a boost ahead of elections due next month.