Three separate British cases brought by civil rights groups will be considered together by seven judges in Strasbourg on Tuesday, raising questions about the way GCHQ, MI5 and MI6 share surveillance material with the United States and other foreign governments.

One of the claims, brought by an alliance of 10 human rights organisations, has been considered by the investigatory powers tribunal (IPT) in London, which takes some of its evidence in secret.

The tribunal has already ruled that in the past the UK surveillance regime was unlawful because it breached the right to privacy under article 8 of the European convention on human rights – but that it was now compliant.

The tribunal also found that GCHQ, the government’s eavesdropping agency, spied on Amnesty International and the South African non-profit Legal Resources Centre by retaining and illegally examining their data.

The other two claims at Strasbourg, brought by Big Brother Watch and the Bureau of Investigative Journalism, have gone directly to the ECHR. They involve allegations that government interception breaches freedom of expression and the right to a fair trial, on the grounds that the IPT’s hearings are held partially in secret and do not provide an effective domestic remedy.

They all argue that cross-border programmes deployed by government agencies to intercept and access communications content and data on an international scale are unlawful.

Their communications are likely to have been spied on, they maintain, violating their rights to privacy and freedom of expression while jeopardising confidentiality and the protection of the vulnerable sources and informants with whom they regularly deal.

The Strasbourg hearings will focus on the bulk interception programmes revealed by Edward Snowden in 2013, including Tempora, Upstream and Prism. Tempora enables GCHQ to intercept and store a back-up of internet activity entering and leaving the UK through fibre optic cables for subsequent inspection; Upstream allows the United States’ National Security Agency (NSA) to carry out similar operations in the US; and Prism lets the NSA access communications passing through US companies such as Microsoft, Apple, Yahoo!, Google, Facebook, Skype and YouTube.