James Kwatia (R) is on trial for causing death by careless driving of Moira Gemmill (L)
Moira Gemmill, 55, was on her way to St James's Palace when she was struck by a Mercedes tipper lorry near Lambeth Bridge in Westminster on April 9 2015.
Harrowing footage played to jurors at the Old Bailey showed the moment the lorry, driven by James Kwatia, pulled away from the bridge on to a roundabout approaching Horseferry Road, crushing Ms Gemmill beneath its wheels and killing her instantly.
Opening Kwatia's trial, prosecutor Mark Gadsden said the 43-year-old had failed to use his mirrors properly and paid insufficient attention to cyclists as he reached the end of the bridge.
Ms Gemmill was crushed to death as she cycled to work by a lorry driven James Kwatia a court heard
He also told the court that Kwatia had positioned his lorry towards the centre of two lanes on the bridge, but as he approached the roundabout he pulled across to his left, leaving no room for Ms Gemmill as she passed by on his near side.
We say it was his driving that was the causation of the accident and the death
Mark Gadsden - Prosecutor
The jury heard that Kwatia had been too preoccupied with traffic on the roundabout to see her, running over her as he accelerated away.
Off-duty police and paramedics tried to save her, but she was declared dead at the scene.
Ms Gemmill, who formerly worked at the Victoria and Albert Museum, had just started a new job as director of capital programmes at the Royal Collection Trust, working on projects at Windsor Castle and Holyrood Palace in Edinburgh.
Mr Gadsden told jurors that Kwatia would have been able to see Ms Gemmill in his mirrors for around eight seconds as he crossed the bridge, and that he should have been aware of her presence and remained straddling the two lanes to give her room.
He said: "Ms Gemmill would have been visible to him in his near-side mirrors as she was coming up on the near side.
"If he remained in that position this accident never would have occurred.
"We say it was his driving that was the causation of the accident and the death."
The accident happened at about 9.30am on April 9, a "dry, clear and sunny morning".
Ms Gemmill crossed Lambeth Bridge from the east side, riding in the cycle lane with another cyclist behind her.
But jurors were told the cycle lane comes to an end near the roundabout, and footage showed her passing Kwatia's lorry to the nearside as they both approached the junction.
Mark Gadsden said 'Ms Gemmill would have been visible to him in his near-side mirrors'
Mr Gadsden said: "His lorry is in the centre of the lane, but coming on to the roundabout itself he cuts right across to the left and therefore allows the cyclist no room.
"As he accelerates away, the cyclist is swept under the lorry and tragically crushed to death."
The prosecutor said while a witness had claimed Kwatia was preoccupied with traffic on the roundabout, when asked after the incident he said he was aware of the cyclists around him.
Mr Gadsden said his driving fell below that of a "careful and competent road user", adding: "He should have known she was there and taken reasonable avoiding action."
Kwatia, from Catford, south-east London, denies causing death by careless driving.
The trial continues.