Polish ambassador to Japan signs controversial ACTA anti-internet piracy agreement in Tokyo; opposition party calls for a referendum.

09.20 - [Scroll down for updates] The signing took place at Japan's Ministry of Foreign Affairs, where ambassador Jadwiga Rodowicz-Czechowska joined her EU counterparts in approving the agreement.

Of the 27 EU member states, Cyprus, Estonia, Slovakia, Germany and Holland did not sign, the latter two citing “procedural grounds”, while simultaneously affirming that they would do so in the near future.

In spite of the hacking of governmental websites since the weekend, Prime Minister Donald Tusk insisted on Tuesday that his government would not “succumb to blackmail.”

Yesterday, large demonstrations against the agreement took place in cities across Poland.

Over 10,000 descended on the Market Square in Krakow, and over 5000 did likewise in the western city of Wroclaw.

In Kielce, central Poland, 24 people were arrested after vandalism to cars and road signs occurred during a demonstration in the city. One policeman was taken to hospital with injuries.

Kamil Tokarski, a spokesman for the Kielce police, said that charges would be brought.

“Policeman dressed in civilian clothes were among the demonstrators," he revealed in an interview with television station TVN.

With governmental web sites, including that of the Prime Minister, still inaccessible owing to hackers, the government has endeavoured to convince the public that the agreement has yet to be ratified in the Polish parliament.

09.27 - Prime Minister Donald Tusk's party, Civic Platform (PO) has posted a '10 myths about ACTA' article on its web site. PO says that ACTA is not a “secret agreement” as critics have suggested. Consultations on the agreement have kept to standards required by the Lisbon Treaty, with the European Parliament informed and MEPs voted on ACTA in November 2010.

PM Tusk's party also say the agreement is in line with international trade law, particularly the so-called TRIPS agreement (Agreement on Trade-Related Aspects of Intellectual Property Rights).

The governing party also says that ACTA is not an attack on individual freedoms but concerns large scale illegal activity, mainly concerning organised crime groups.

ACTA obliges ISPs to monitor content put onto the web by users but does not contain a “three strikes and out” clause, as has been claimed, says the government.

09.45 - Minister for Digitalization Michal Boni admits the government has “got a scolding” over signing ACTA. “We are entering a new era of dispute related to a new '2.0 generation'. For young people, the most important sphere of freedom is on the internet and not as it was for my geberation – an independent Poland,” the minister has told Polish Radio.

10.01 - A special task force has reportedly been convened to work out how to protect government web sites from attack by Anonymous and other online protest groups, says spokesman for the Ministry of Digitalization, Artur Koziołek. (PAP)

10.18 - Liberal Dutch Marietje Schaake Member of the European Parliament has posted a statement on Reddit, where she argues: "As a Member of the European Parliament (EP), I am concerned about the ACTA treaty in the international trade committee... The internet blackouts by thousands of websites last week in protest of the Stop Online Piracy Act (SOPA) and the Protect Intellectual Property Act (PIPA) have raised lively discussions."

10.45 - Poland civil rights Ombudsman Irena Lipowicz has told the TVP public broadcaster that she has requested the government to explain why the signing of the ACTA agreement has taken place with little or no public consultation. She says that before the signing of the agreement took place this morning the matter should have been debated in parliament.

11.34 - Local police spokesman for the Kielce district Kamil Tokarski said that they are currently examining CCTV footage of the rioting that took place in the southern city last night in protest against the ACTA agreement. Currently 28 mostly young people have been arrested. More will follow today, he added.

11.38 - Strong words from senior Civic Platform MP Stefan Niesiolowski this morning. He has called ACTA opponents who rioted in Kielce last night “idiots”. He told Radio Zet that when ACTA comes before parliament for ratification he will vote for it.

12.20 - Jaroslaw Kaczynski, leader of Poland's largest opposition party Law and Justice (PiS) has said he will table a motion in parliament for a referendum to be held on ratifying ACTA .

“In this great debate about the ACTA proposal we will put forward [the motion] that there is a referendum to decide the final decision of our government on this issue,” Kaczynski said at a press conference this morning.

12.35 - Wanda Nowicka, an MP for the liberal Palikot Movement (RP) and a deputy speaker of the lower house of parliament has written to the minister of administration and digitization Michal Boni, asking whether ACTA does not violate Poland's constitution.

12.40 - If you want to know what all the fuss is about then have a read of the complete text of the agreement as released by the European Commission last May.

13.15 - The Polish parliament web site is loading intermittently today. There have also been reports that foreign minister Radek Sikorski's personal web site crashed this morning but it appears to be working at present. The Prime Minister's Office web site is also working. Despite threats from Anonymous hackers, state web sites are functioning following Poland signing the ACTA agreement in Tokyo, unlike at the weekend when web sites were crashing, left, right and centre.

Online reporting by Peter Gentle and Nick Hodge