The pilot who died when his helicopter crashed into a crane continued to fly, despite several warnings about freezing fog.
Pete Barnes, 50, was killed after his lightweight Agusta 109 helicopter crashed into the crane on top of St George's Wharf Tower, on Nine Elms Lane, last week.
Pedestrian Matthew Wood, 39, of Sutton, was also killed after being struck by burning debris.
A report released by the Air Accidents Investigation Branch (AAIB) today revealed Mr Barnes was ignored warnings not to fly by a fellow pilot and his client waiting at Elstree aerodrome as visibility was poor.
It said: "At 07:18hrs, the client called the pilot to discuss the weather. The pilot said he thought the weather might clear earlier than forecast.
"The client said he would drive to Elstree and call the pilot to keep him advised."
Just before 7am another pilot aware of the journey messaged him: "Give me a call as I have checked weather and freezing fog around at the moment."
But Mr Barnes replied: "I’m coming anyway will land in a field if I have to."
The report also shows the pilot originally made his final destination at Elstree at 7.48am, but he diverted back towards Redhill owing to the poor visibility.
A radio conversation between Mr Barnes and air traffic control seconds before the crash shows he was aiming to divert to Battersea Heliport.
After being told it was open he said: "If I could head to Battersea that would be very useful."
The controller asked Mr Barnes to hold on the river between Vauxhall and Westminster, before approving the diversion to Battersea.
His final words were "Thanks a lot."
All pilots had been given a warning that a crane reaching up to 800 feet would be on top of St George's Wharf between January 7 and March this year.
Despite this the report states the helicopter was at 800 ft when Mr Barnes altered his course after being given clearance to come into Battersea.
The tail of the helicopter struck St George's Wharf Tower and immediately fell to the ground, creating a shallow crater and rupturing a water main.
It's fuel tanks ignited and set two cars on Wandsworth Road alight, with the one closet to the wreckage completely consumed by fire.
The report said: "The tail section of the helicopter detached from the tail boom as the helicopter made contact with a building, before the fuselage struck the ground."
Although the report provides no analysis and offers no conclusion it cites rules a section from the Manual of Air Traffic Services.
It states: "The pilot of an aircraft on a Special VFR (visual flight rules) flight is responsible for ensuring that his flight conditions enable him to remain clear of cloud, determine his flight path with reference to the surface and keep clear of obstructions.’