May 20, 2013: Edward Snowden, an employee of defence contractor Booz Allen Hamilton at the National Security Agency, arrives in Hong Kong from Hawaii. He carries four laptop computers that enable him to gain access to some of the U.S. government’s most highly-classified secrets.

June 1, 2013: The Guardian's journalists Glenn Greenwald and Ewen MacAskill and documentary maker Laura Poitras fly from New York to Hong Kong. They meet Snowden in a Kowloon hotel after he identifies himself with a Rubik’s cube and begin a week of interviews with their source. | ‘I can’t allow the US government to destroy privacy’

June 5, 2013: The Guardian publishes its first exclusive based on Snowden’s leak, revealing a secret court order showing that the U.S. government had forced the telecom giant Verizon to hand over the phone records of millions of Americans.

June 6, 2013: A second story reveals the existence of the previously undisclosed programme Prism, which internal NSA documents claim gives the agency “direct access” to data held by Google, Facebook, Apple and other US internet giants. The tech companies deny that they have set up “back door access” to their systems for the U.S. government.

June 7, 2013: Barack Obama defends the two programmes, saying they are overseen by the courts and Congress. Insisting that “the right balance” had been struck between security and privacy, he says: “You can’t have 100% security, and also then have 100% privacy and zero inconvenience.” The Guardian reports that GCHQ has been able to see user communications data from the American internet companies, because it had access to Prism.

June 8, 2013: Another of Snowden’s leaks reveals the existence of an internal NSA tool — Boundless Informant — that allows it to record and analyse where its data comes from, and raises questions about its repeated assurances to Congress that it cannot keep track of all the surveillance it performs on American communications. | Under cover of darkness

June 9, 2013: Snowden decides to go public. In a video interview he says: “I have no intention of hiding who I am because I know I have done nothing wrong.” | “I do not expect to see home again”

June 10, 2013: Snowden checks out of his Hong Kong hotel.

June 12, 2013: Hong Kong’s South China Morning Post publishes the first interview with Snowden since he revealed his identity. He says he intends to stay in the city until asked to leave and discloses that the NSA has been hacking into Hong Kong and Chinese computers since 2009. | China hits out at ‘double standards’

June 14, 2013: The Home Office instructs airlines not to allow Snowden to board any flights to the U.K.

June 16, 2013: The Guardian reports that GCHQ intercepted foreign politicians’ communications at the 2009 G20 Summit.

June 20, 2013: Top secret documents published by The Guardian show how U.S. judges have signed off on broad orders allowing the NSA to make use of information “inadvertently” collected from domestic US communications without a warrant.

June 21, 2013: A Guardian exclusive reveals that GCHQ has gained access to the network of cables which carry the world’s phone calls and internet traffic and is processing vast streams of sensitive personal information it shares with the NSA. | The U.S. files espionage charges against Snowden and requests that Hong Kong detain him for extradition.

June 23, 2013: Snowden leaves Hong Kong on a flight to Moscow. In a statement, the Hong Kong government says documents submitted by the US did not “fully comply with the legal requirements under Hong Kong law” and it had no legal basis to prevent him leaving.

June 24, 2013: Snowden, who has been expected to fly to Cuba on the only direct flight to Latin America from Moscow's Sheremetyevo airport, fails to take seat booked in his name. | Moscow pleads ignorance of Snowden's whereabouts

June 25, 2013: Russia rejects U.S. demand for Snowden extradition | Putin against extraditing Snowden

June 26, 2013: China hits out at U.S. accusations on Snowden | Snowden spends fourth day at Sheremetyevo | ‘Clear legal basis’ to expel Snowden: U.S.

June 27, 2013: Ecuador renounces trade benefits from U.S. Congress | Asylum request could be considered: Kremlin

June 29, 2013: Assange ‘apologises’ over Snowden asylum row

June 30, 2013: Ecuador revokes safe passage documents issued to Snowden, Kremlin makes it clear it saw him as a headache

July 1, 2013: Putin repeats his refusal to hand over Snowden to the U.S. | ‘Snowden stowed away trove of secrets’

July 2, 2013: Snowden seeks asylum in 20 countries, including India; New Delhi turns down request

July 3, 2013: Rejecting allegations of political vendetta, the U.S. has said Edward Snowden is rightfully charged by its courts for espionage and leaking classified information and Washington is making diplomatic efforts to ensure he is brought back to face those charges.

July 5, 2013: Icelandic lawmakers have introduced a proposal in Parliament to grant immediate citizenship to Edward Snowden, who admits to revealing key details of U.S. surveillance activities.

July 6, 2013: Nicaragua, Venezuela offer asylum to Snowden

July 12, 2013: Snowden seeks asylum for second time in Russia.

July 12, 2013: 'The willingness by powerful states to act extra-legally represents a threat to all of us'. Transcript of Edward Joseph Snowden's statement, given in Moscow on Friday.

July 26, 2013: Russia will not extradite Snowden, says Putin’s aide

July 30, 2013: Washington assures Moscow that Edward Snowden will not be executed if sent back home, but Moscow reiterates its refusal to deport the whistleblower.

August 1, 2013: Russia grants asylum to Edward Snowden | US ‘extremely disappointed’

Sources: The Guardian, AP, The Hindu