Emergency services were called to the scene at the junction of Bedfont Road and Long Lane at 11.39pm following the collision between a white Mercedes HGV and a white Toyota Yaris. The HGV left the road and ended up in Longford River, which runs parallel with Bedfont Road.
Two men aged 25 and 23 and a woman aged 20 who were in the Yaris died at the scene, and a 25 year-old woman, also in the Yaris is in hospital in a serious condition. Their next of kin have been informed.
The driver of the lorry was taken to hospital as a precaution. No arrests have been made. The road remains closed while recovery of the HGV takes place this morning.
Sergeant Chris Schultze from the Surrey and Sussex Roads Policing Unit said: “Our thoughts are with the family and friends of those involved in this collision at what is an extremely difficult time.
“We are continuing to appeal for witnesses to what happened and would urge anyone who may have any video footage, CCTV or dashcam or any other kind, to get in touch with us. Please report any information via 101 and quote the reference number PR/P19303422.”