"I do like the royals, but the way my sister's life has been endangered is complelely unacceptable. These outriders need to slow down."
Clearly emotional, Ms Shore added: "But it will still go on. I doubt anything will change just because a lady speaks out over concern for her sister."
Irene was hospitalised in a critical condition and the Duke and Duchess of Cambridge were left shaken, following the devastating collision involving their convoy.
It has emerged that the couple were on their way to Windsor for the Order of the Garter festivities when a police motorcycle accompanying their car struck Irene, 83, in south-west London.
It has been reported that the motorcyclist may have been on the wrong side of the road as part of his duties to clear traffic.
Irene was reportedly thrown into the air by the impact and landed awkwardly, breaking her pelvis and sustaining other injuries. She was hospitalised, with the royal being kept up to date on her condition.
‘The Duke and Duchess of Cambridge were deeply concerned and saddened to hear about the accident on Monday afternoon,’ Kensington Palace confirmed in an official statement. ‘Their Royal Highnesses have sent their very best wishes to Irene and her family and will stay in touch throughout every stage of her recovery.'