The collision comes after a tumultuous few months for the I'm A Celeb star, who booked himself into a rehab clinic past year after becoming hooked on painkillers and is now divorcing his wife Lisa.
A child passenger in one of the cars was taken to hospital for a check up as a precaution, the Met added.
Ant McPartlin has been arrested by police following a reported "drink-driving crash" that lead to a girl aged 3 visiting hospital.
The Metropolitan Police confirmed this morning that the ITV presenter had been released from custody at a south London police station, after officers questioned him over the collision.
A Scotland Yard spokesman said: "Police in Richmond were called to Lower Richmond Road, SW14 at 15:59hrs on Sunday March 18 following reports of a road traffic collision involving three vehicles".
While detailing the events of yesterday afternoon, the reporter stumbled over his words and referred to Dec as Ant's "friend" as he struggled to remember his name.
Ant and Dec
Ant went to rehab last summer for his prescription painkiller addiction after he underwent an unsuccessful operation on his knee. Get Me Out Of Here! in November, where the show even made several scripted digs at his experience with rehab.
Ant also split from his wife of 12 years Lisa Armstrong.
At the National Television Awards a few days after the split, Ant referred to his "tough year" while picking up the presenting prize with December.
The Saturday Night Takeaway and I'm a Celebrity.
ITV has yet to comment on the programme, which is scheduled to air live on Saturday at 7pm.
Witnesses said McPartlin was said to look "dazed" and "like his world had just ended" at the time of his arrest but was more confrontational in the immediate aftermath, becoming "agitated and argumentative" with a policewoman.
PM To Wrap Up Asean Pow Wow
They also agreed to regional dialogues and workshops covering electronic evidence, financial intelligence, and ways to tackle online radicalisation.