Polish lawmakers on Wednesday called for a boycott of Britain's Tesco supermarket chain amid a high-pitched British row over benefits for EU migrants. British Prime Minister David Cameron, reacting to public fears that central Europeans from poorer EU states could arrive to leach off Britain's welfare system, last month had migrants' access to unemployment benefits tightened. He recently floated the idea of ending benefit payments for children living in their home country while their parents work in Britain. He also caused an uproar in Poland by pointing the finger at Polish migrants who constitute the largest single group to have arrived in Britain after the EU's 2004 expansion. "It's time to say no to Cameron's politics and we urge Poles to boycott Tesco stores when they go shopping," PSL parliamentary caucus head Jan Bury said Wednesday in Warsaw. His governing centre-right party holds just 33 seats in Poland's 460-seat parliament. "We can't just stand by and watch as Premier Cameron keeps insulting Poles and attacking Polish families," Bury added. Tesco employs around 30,000 people in Poland and has invested around 2.4 billion euros ($3.25 billion) in a nation-wide chain of stores. Centre-right Prime Minister Donald Tusk waded into the row on Tuesday, insisting Poland would veto any proposed changes to welfare benefits for migrant workers at the EU level. In talks with Tusk via telephone on Wednesday Cameron stuck by his view that "the lack of transitional controls for new EU member states in 2004 was the wrong approach", a statement issued by his Downing Street office said. "We need to address the impact on countries’ benefits systems, including for example paying child benefit to families living abroad," it said. The leaders agreed on looking into "how the UK and Poland can work together to better manage the impact of intra-EU migration on social security systems". Hundreds of thousands of immigrants from eastern EU states have made Britain their home since the bloc's "big bang" expansion in 2004. Britain and Ireland were among the few older members to fully open their labour markets to newcomers a decade ago. Cameron has termed that open-door policy a "monumental mistake", provoking ire in Poland with anti-communist legend Lech Walesa insisting he was being "shortsighted" and "unreasonable" on the issue. On Monday, the British prime minister was also criticised for his comments by Polish Foreign Minister Radoslaw Sikorski. "If Britain gets our taxpayers, shouldn't it also pay their benefits?" Sikorski asked in English on Twitter. "Why should Polish taxpayers subsidise British taxpayers' children?" Around 640,000 Poles live in Britain, according to official statistics released in 2012, but the Polish community estimates the real figure might be as high as one million. Some Conservative backbenchers and right-leaning newspapers in Britain have whipped up worry over a massive influx of Romanians and Bulgarians following the relaxation of EU labour market restrictions on January 1.