[JURIST] The Council of Europe [official website] said Wednesday that an investigation into allegations that the US Central Intelligence Agency operated secret prisons [JURIST report] in Europe revealed no "smoking gun" evidence that proved the existence of the prisons. COE Secretary General Terry Davis [official profile], presenting his findings on alleged illegal detentions and rendition flights on European territory based on official replies received from all 46 COE member states, also said that it was "virtually impossible" to determine whether the CIA used European airspace for extraordinary rendition [JURIST news archive] in violation of the European Convention on Human Rights [PDF text].

In a press conference [prepared statement; recorded video] Wednesday, Davis said however, that "Europe appears to be a happy hunting ground for foreign security services" and urged European nations to adopt tougher laws [press release] to guarantee "effective oversight over the activities of foreign agencies on their territory." According to the executive summary of his report [PDF text; COE materials], there are four areas where action should be taken:

the rules governing activities of secret services appear inadequate in many States; better controls are necessary, in particular as regards activities of foreign secret services on their territory;

the current international regulations for air traffic do not give adequate safeguards against abuse. There is a need for States to be given the possibility to check whether transiting aircraft are being used for illegal purposes. But even within the current legal framework, States should equip themselves with stronger control tools;

international rules on State immunity often prevent States from effectively prosecuting foreign officials who commit crimes on their territory. Immunity must not lead to impunity where serious human rights violations are at stake. Work should start at European and international levels to establish clear human rights exceptions to traditional rules on immunity;

mere assurances by foreign States that their agents abroad comply with international and national law are not enough. Formal guarantees and enforcement mechanisms need to be set out in agreements and national law in order to protect ECHR rights.

Interim COE reports prepared by Swiss legislator Dick Marty, leading a separate inquiry by the COE's parliamentary assembly [JURIST report], have asserted that secret CIA prisons had existed in Europe [report text, PDF; JURIST report], but have so far acknowledged there is no concrete proof of their actual existence. Reuters has more.