Poles will be richer than Britons in five years’ time because of Brexit, Donald Tusk, the prime minister of Poland, has said.

Mr Tusk was European Council president during the Brexit negotiations and was notorious among Brexiteers for his scathing criticism of the decision to leave the EU.

He referred to a Labour forecast based on World Bank data that said Poland would outstrip the UK in gross domestic product (GDP) per capita by 2030.

“A fierce debate is taking place in Great Britain caused by the World Bank’s forecast that GDP per capita will be higher in Poland than in the UK in 2025,” Mr Tusk said on the 20th anniversary of Poland’s membership of the EU.

“And I promise this: on the 25th anniversary, Poles will be richer than the British. It’s better to be in the EU,” he said on social media on Wednesday.

Sir Keir Starmer, the Labour leader, in February used the World Bank data to bolster his arguments for a change of government at the next election.

The Office for National Statistics estimated the Polish-born population of the UK was 691,000 in 2020. The most spoken non-native language in Britain is Polish and it is estimated almost a million Poles lived in the UK before the 2016 Brexit referendum.

‘A special place in hell’

Mr Tusk won his second stint as prime minister, a job he left to become European Council president, in the Polish general election last year. He campaigned on a pro-EU ticket against the nationalist Law and Justice government.

While in Brussels, he caused fury when he said there was “a special place in hell” for Brexiteers who had campaigned in 2019 for Brexit without “even a sketch of a plan”.

Mr Tusk prompted a dispayed response after posting a picture on Instagram of him offering Theresa May a cake at a tense 2018 summit in Salzburg.

The then former prime minister of Poland captioned the shot with the words, “sorry no cherries”.

The joke was a reference to the regular accusations from Brussels that Britain wanted to “have its cake and eat it” in the Brexit negotiations by “cherry-picking” access to the Single Market.

But after the Salzburg summit turned into a humiliation for Mrs May there was anger over the picture in Britain.

The Labour forecast is based on the idea that GDP per capita grows at an average of 0.5 per cent each year in real terms, as it did between 2010 and 2021.

The World Bank data shows GDP per capita in 2021 was $44,979 (£35,935) in Britain and $34,915 (£27,894) in Poland, which has an average growth of 3.6 per cent annually.

That would mean Poland would overtake the UK by 2030, according to the calculations.