(Telecompaper) The European Court of Justice (ECJ) has ruled that the 'safe harbour' agreement on data transfer between the EU and US is invalid, casting doubt on the extent to which US tech giants such as Facebook, Google and Apple can continue to collect data from their users in the EU. The ECJ's ruling upholds the opinion of its advocate-general Yves Bot, who last month said the 'safe harbour' deal should be invalidated "because the surveillance carried out by the US is mass, indiscriminate surveillance," leaving the data of European citizens unprotected in the US. The agreement has been in force since 2000 but has come under severe criticism following revelations of widespread US spying from former National Security Agency contractor Edward Snowden.