-97. The principle of cooperation set out in the Convention also requires that decisive action be taken to improve the situation in the light of the Committee's recommendations. The CPT notes that the Greek authorities have taken certain measures in response to the recommendations made by the Committee after previous visits (cf. for example, paragraph 31). The CPT welcomes the measures taken; however, there is still much to be done and the authorities need in particular to invest greater efforts to tackle the systemic deficiencies in the prison service and the establishments holding foreigners nationals. Consequently, the Committee has been obliged to reiterate many of its recommendations, some of which are of very long standing. Having regard to Article 3 of the Convention, the CPT urges the Greek authorities to intensify their efforts to improve the situation in the light of the Committee's recommendations. The CPT must stress that a persistent non-implementation of its recommendations by the Greek authorities will leave the Committee with no choice but to set in motion the procedure provided for in Article 10, paragraph 2, of the Convention1. The Committee trusts that the action taken in response to this report will render such a step unnecessary. E. Immediate observations under Article 8, paragraph 5, of the Convention 8. At the meeting which took place at the end of the visit on 9 September 2005, the CPT's delegation made three immediate observations under Article 8, paragraph 5, of the Convention as regards the follow-up to cases of alleged ill-treatment at Venna Special Holding Facility, the unacceptable conditions of detention in the Peplos and Mytilini Special Holding Facilities and the multiple shortcomings at Chios Judicial Prison. The Greek authorities were requested to provide the CPT, respectively, with:  by 15 October 2005, a full report on the situation of the eleven persons who alleged that they had been ill-treated at the Venna Special Holding Facility, including the results of a medical examination certifying any physical injuries which they may bear, and a general assessment of their state of health;  by 31 October 2005, information on the action taken to improve the conditions of detention in the Peplos and Mytilini Special Holding Facilities, including improving sanitary facilities, access to health care, the provision of purposeful activities and increased, and more diverse, staffing levels;  by 15 November 2005, specific information on reducing overcrowding and improving material conditions, staffing, health care provision and regime, in respect of Chios Judicial Prison. 9. By letters of 9 November 2005 and 12 January 2006, the Greek authorities informed the CPT of measures taken in response to the immediate observations and on other issues raised by the delegation at the end of the visit. These responses have been taken into account in the relevant sections of the present report. 1 Article 10, paragraph 2, reads as follows: "If the Party fails to co-operate or refuses to improve the situation in the light of the Committee's recommendations, the Committee may decide, after the Party has had an opportunity to make known its views, by a majority of two-thirds of its members to make a public statement on the matter".