The row between Poland and the European Union has escalated after the EU warned Warsaw that it would remove its voting rights in the EU, if the Polish Government did not roll back controversial changes to its Constitutional Court - a sanction never before exercised in the EU.

However, the warning comes two months after the expiration of the time period from the previous warning, in a move criticized by some as showing weakness on the part of the Brussels administration. Poland is under investigation by both the European Commission and the Council of Europe over controversial changes to the Polish constitution brought in when Beata Szydło's Law & Order party won the 2015 elections.

In December 2015, the Polish Government added five 'politically friendly' judges to the country's Constitutional Tribunal, in a move seen by critics as making it easier to push through legislation with less opposition.

The amendment meant that the tribunal would need a two-thirds majority to take a decision on constitutional matters instead of a simple majority. The minimum number of judges needed to make a decision was also raised from nine to 13, making it more difficult to convene a quorum.

Despite a series of discussion between Brussels and Poland involving minor amendments to the Constitutional Court changes, the European Commission maintains that Poland is in breach of the fundamental principle of the 'Rule of Law' within the EU.

In a statement, December 21, the Commission said: "It is enshrined in Article 2 of the Treaty on European Union. The European Commission, together with the European Parliament and the Council, is responsible under the Treaties for guaranteeing the respect of the rule of law as a fundamental value of our Union and making sure that EU law, values and principles are respected."