Geremek, 76, was a leading member of the trade union that helped topple communism in Poland.

The activist-turned-politician had been serving as a member of European Parliament since his election in 2004. But he is well-known in Poland as one of the key advisers to Lech Walesa, the Solidarity union leader.

Born in Warsaw on 6 March 1932, Geremek earned a doctorate in medieval history in 1960 from the Polish Academy of Sciences, where he later became a professor.

He quit the Polish Communist Party in 1968 to protest against the Warsaw Pact's invasion of Czechoslovakia to crush the Prague Spring.

He served as Poland’s foreign minister from 1997 to 2000, during which time he oversaw the country’s accession to NATO.

On his election to the European Parliament in 2004, Geremek joined the Alliance of Liberals and Democrats for Europe.

He died on Sunday 13 July when his Mercedes collided with an oncoming vehicle in western Poland, a police spokeswoman said. It was not immediately clear whether he was driving at the time.