New Delhi:Queen Elizabeth II died at 96 today.The 96-year-old monarch had been dogged by health problems since October last year that left her with difficulties walking and standing.Her closest family travelled to join her on Thursday after doctors placed her under medical supervision before she died.

Earlier this month,leaked documents revealed the extent of a huge operation to be made active just after Queen Elizabeth II dies.

Details of"Operation London Bridge"were leaked to Politico,which said officials would refer to the day the Queen dies as"D Day".

The code for conveying the message that the Queen has died would be-"London bridge is down."

A vast security operation has been planned to manage the unprecedented crowds and travel chaos expected in the lead-up to her funeral,news agency PTI reported.

One memo warned that London could be stretched to breaking point as hundreds of thousands of people make their way to the capital.

There would be a supposedly"spontaneous"service at St Paul's Cathedral,according to Politico,and the new King Charles would tour the four nations of the United Kingdom in the days after her death.