In the days before the invasion British intelligence became aware that a military crisis was fast approaching. Preparations to send a task force to repossess the Falklands began three days before they were invaded.
Once it broke, the news of the invasion exploded like a political bombshell. Parliament was recalled on a weekend for the first time in decades.
The Foreign Secretary, Lord Carrington, and two junior ministers had resigned by the end of the week. They took the blame for Britainís poor preparations and plans to decommission HMS Endurance, the navyís only Antarctic patrol vessel. It was a move which may have lead the Junta to believe the UK had little interest in keeping the Falklands.
By 5 April the first battle ships, including two aircraft carriers, hurriedly set sail for the South Atlantic. In all, Britain sent over 100 ships and 27,000 personnel to take part in the war.
By then Britainís cause had already won the backing of the UN. The Security Council voted 10-1 backing a resolution that demanded the immediate withdrawal of Argentinean forces from the Falklands.
Keen to prevent a full scale war arising the US Secretary of State Alexander Haig used the two to three weeks it would take the UKís fleet to reach the South Atlantic to try and find a diplomatic solution.
But by 19 April Mr Haigís shuttle diplomacy had failed. And although the UN continued attempts to find a peaceful solution full-scale war was becoming inevitable.