The British government applied to take Britain into the European Common Market several times in the 1960s, but France always blocked the idea. Eventually, in 1973, the Conservative Prime Minister Edward Heath was successful in negotiating British membership. The Common Market was initially focused on trade in goods and agriculture.
Eastern Europe had been part of the communist bloc in the Cold War years after 1945, and there was almost no communication or movement of people between West and East for nearly fifty years. At the end of the 1980s, the Soviet Union and its Eastern bloc collapsed, and the armed division of Europe came to an end.
In 2004 ten Eastern European countries, including Poland, joined the EU and migrants were able to travel to Britain and work. In 2007 Bulgaria and Romania were admitted to the EU and many of their citizens also migrated to Britain.