The Polish parliament on Thursday delayed ratifying the Lisbon treaty following an attempt by the opposition Law and Justice party to insert a preamble stating that Poland is a sovereign country and its constitution is the highest law in the country. The move by Law and Justice is unexpected because the party’s leaders Lech Kaczynski, the president, and Jaroslaw Kaczynski, his twin brother and the former prime minister, negotiated the treaty with other EU members last December, then proclaimed it a success.

Now in opposition, Jaroslaw Kaczynski has bowed to the eurosceptical views of some of his more right-wing and fervently Catholic supporters who are worried about Poland allowing gay marriages or Germans trying to reclaim property lost after the war. Mr Kaczynski accuses Donald Tusk, the prime minister, of weakening Poland’s position by saying he will give up opt-outs to the treaty won during the negotiations.