The Words The SEAL Killing Osama bin Laden Radioed Home

Yet despite how close it came to ending in disaster after the first Black Hawk crash-landed, insiders describe it as a straightforward raid, and one the highly-trained Navy SEALs were more than used to carrying out.

One said: 'This wasn’t a hard op. It would be like hitting a target in McLean [the upscale Virginia suburb of Washington D.C.]'

Advisers including Gates had suggested it would be better not to have American troops on the ground in Afghanistan, but Mr Obama baulked at the idea of an airstrike when he learned the ordnance needed to smash through underground bunkers would 'be the equivalent of an earthquake.'

The president had no intention of destroying a city. So he put his faith in a 23-man team of SEALs from Red Squadron, part of the legendary Team Six, known as DEVGRU, the Naval Special Warfare Development Group.

They had begun planning some kind of raid in late 2010, soon after agents first discovered the compound where they believed Bin Laden was hiding, according to a senior operations officer 'deeply familiar' with the raid.

After weeks of deliberating, senior officials settled on the most dramatic option - flying straight into the compound They decided tunnelling was too risky, as the house was built on a flood plain, and it would be too dangerous for the soldiers to land outside the city and go in.

An insider said: 'Special operations is about doing what’s not expected, and probably the least expected thing here was that a helicopter would come in, drop guys on the roof, and land in the yard,'

According to a senior adviser to the president, there was never any question of telling Pakistan about the mission. He told Schmidle: 'There was a real lack of confidence that the Pakistanis could keep this secret for more than a nanosecond.'

He said: 'That was a pretty good idea, too.'

But Obama vetoed his idea of an airstrike and gave Vice Admiral Bill McRaven, the SEAL in charge of JSCO, the Joint Special Operations Command, the go-ahead to start rehearsing the raid.