British spies reportedly monitored the Russian invasion of Ukraine by tracking Vladimir Putin's soldiers who were using dating app Grindr and other social networking sites.
Russia launched its invasion of Ukraine 11 days ago and UK spies are said to have been increasingly certain of Putin's plans after tapping into social media messages.
The intelligence services gave the information to Ukraine to help in anticipation of a full-scale invasion, only keeping back some details to protect sources and methods.
Putin banned dating apps such as Grindr in 2013 but it is still used and provided a "treasure trove" of information for British spies.
Intelligence services also tracked messages on the Russian equivalent of Facebook - VKontakte.
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A source told the Daily Mail: "These sites were a treasure trove for our spies, and the dating apps in particular – soldiers and those involved in the military effort were particularly unguarded.
"It meant we were very au fait with the plans and the imminence of the invasion, right down to details such as the movement of blood supplies to the Russian troops."
It comes as brave Ukrainians marched towards Russian troops in the city of Melitopol and told them to "go home", forcing the soldiers to retreat while firing their guns above the demonstrators' heads.
Citizens had been given a five hour window to flee the bombed-out city, only for fighting and strikes to cause many to immediately seek shelter or return to their homes.
Crowds hailed President Volodymyr Zelensky, chanting “Zelensky is a good guy, Putin’s a f***ing jerk”.
And efforts to evacuate Mariupol were halted as Russian shelling of escape routes continued despite a ceasefire.
Ukrainians trying to flee the city during a five-hour ceasefire had to seek shelter after Russian forces continued shelling, it has been reported.
Many had to turn back as it became clear that shelling had continued and fighting had broken out near the evacuation route.
"It's not safe to go by this road because of these fights," the city's deputy mayor Serhiy Orlov told the BBC.
Among Britain's continued support for Ukraine, two battle-ready selfless young Brits with no military experience have gone to risk their lives to fight alongside Ukrainian troops.
The pair didn't even tell their parents they were heading for the war zone for fear they would try to change their minds.
Inexperienced Matt Harden, 25, from Liverpool and brave teenager Steven, from Scotland, met up with an Algerian-Australian man, aged 24, online.
They first spoke through Discord, an online chat room popular among gamers. From there, they hatched their plan to join the international legion.
