How social networks acknowledged activity by Russian trolls

New data has shed more light on the scope of activity by Russian-linked accounts in targeting UK.

MPs have been asking Twitter and Facebook to investigate any activity linked to Russian accounts on their platforms since autumn 2017.

Here is how the networks slowly acknowledged activity from Russian trolls on their platforms:

- September 6 2017

Facebook says 470 Russian accounts posted 3,000 ads on the platform between 2015 and 2017, largely aiming to stoke divisions between communities in the US. A further 2,200 ads were deemed suspicious and all were reported to US authorities.

- September 28 2017

Twitter says 22 of the 470 Russian accounts which Facebook found had corresponding accounts on Twitter, leading them to a further 179 accounts which also violated the network's rules.

- October 16 2017

Twitter announces that it has banned the Kremlin-funded news organisations RT and Sputnik from advertising on its platform based on "retrospective work" around the 2016 US election.

- October 19 2017

Damian Collins, chairman of the UK parliamentary inquiry into fake news, writes to Facebook founder Mark Zuckerberg about Russian-linked accounts targeting the Brexit vote and 2017 general election. Mr Collins asks for any information about adverts paid for by Russian-linked accounts.

- October 30 2017

Google says it has identified 18 YouTube channels linked to the Internet Research Agency which posted more than a thousand videos, as well as two Google accounts which had spent 4,700 dollars on adverts during the 2016 US election cycle.

- November 1 2017

Facebook, Twitter and Google give evidence to the US Senate Select Committee on Intelligence.

Facebook says the 470 accounts it had previously identified are linked to the Russian Internet Research Agency. Those accounts posted to Facebook more than 80,000 times between 2015 and 2017, posts which may have been seen by "approximately" 126 million people.

Twitter says it has so far identified 2,752 accounts linked to the Internet Research Agency which sent more than 131,000 tweets during the US election campaign period.

- November 2 2017

The Electoral Commission says it has asked Twitter and Facebook to investigate any Russian attempts to influence the Brexit vote.

- November 3 2017

Mr Collins writes to Twitter chief executive Jack Dorsey asking for a list of Internet Research Agency-linked accounts and "any posts from these accounts which are linked to the United Kingdom".

- November 14 2017

Research from the University of Edinburgh reveals 419 accounts of the 2,752 Internet Research Agency-linked accounts identified by Twitter had posted about Brexit a total of 3,468 times.

- December 13 2017

Twitter and Facebook respond to the Electoral Commission request for information about Russian adverts targeting the Brexit vote. Based on the investigations they previously carried out into accounts targeting the US, Twitter identified six ads from Kremlin-backed broadcaster RT costing £1,000 and Facebook says Russian accounts spent just £0.97 seen by 200 people.

Mr Collins slams Facebook's response, saying "it would appear no work has been done by Facebook to look for other fake accounts" and repeats the request from his October 24 letter to Mr Zuckerberg.

Twitter also sends its response to the Electoral Commission to Mr Collins.

- December 14 2017

Mr Collins calls Twitter's reply "completely inadequate" and repeats his request for any posts "linked to the United Kingdom".

- January 17 2018

Facebook says it will expand its investigation looking for "co-ordinated activity around the Brexit referendum".

- January 19 2018

Twitter says it has found an additional 1,062 Internet Research Agency-linked accounts which targeted the US election, bringing the total to 3,814 accounts posting 175,993 tweets during the 2016 US election period.

Information about the accounts is submitted to Congress but not made public.

- January 31 2018

Twitter says it has contacted 1.4 million people in the US to tell them they may have seen tweets posted by Internet Research Agency-linked accounts.

- February 8 2018

Representatives from Twitter, Facebook and Google give evidence to the parliamentary fake news inquiry in Washington, the first time such a hearing has taken place outside the UK.

Twitter tells MPs it has found a further 49 accounts linked to the Internet Research Agency which posted 942 times during the Brexit campaign. No details are provided to the inquiry or made public.

Google says it has found no evidence Russian accounts created adverts targeting the Brexit vote. Facebook provides no new evidence.

- February 16 2018

A US grand jury charges the Internet Research Agency, two other organisations and 13 Russian individuals with conspiracy to defraud the United States as part of a campaign to influence the US election.

- February 28 2018

Facebook says it has found no new Russian-linked accounts posting adverts about the Brexit vote.

- March 10 2018

NBC News releases an interview with Vladimir Putin, in which the Russian president denies any Kremlin involvement with attempts to interfere in the US election.

- March 13 2018

New research reveals at least 154 Internet Research Agency-linked accounts sent more than 2,400 tweets targeting the 2017 general election, Brexit and UK politics.

MPs demand Twitter look again for Russian activity targeting the UK while academics call for social networks to open up their archives for further study.