Carrington had earlier outlined the UK's position, saying that his government only backed Solidarity out of respect for public opinion, but that perhaps, from a more rational position, they would actually be "on the side of the Polish government".
Back then, Warsaw was threatened with insolvency and Thatcher evidently feared that the demands of the workers' movement could trigger a Soviet invasion. A few months later, the Polish communist Leader Wojciech Jaruzelski imposed martial law and the US invoked economic sanctions against Poland. Britain, however, avoided levying sanctions on the country.Presumably it was the “trade-union-led” bit that swung Solidarność into the same category as Nelson Mandela (considered a terrorist by the Thatcher government); after all, even if they might overthrow an evil Communist regime, what if in doing so they cause the greater harm of giving the local unionists ideas? In which case, Jaruzelski would have been a bulwark of stability, sort of like Thatcher's close friend, General Pinochet.
This wasn't Thatcher's last attempt to shore up the Eastern Bloc; later, as the Berlin Wall fell, she flew to Moscow to press Gorbachev to stop the reunification of Germany. Presumably freedom was good only where it applied to capital.