Detectives investigating a knife-point robbery where two high-value watches were stolen are appealing for information and witnesses.

The victim, a 42-year-old man, was targeted by a moped rider and his pillion passenger in Duke Street near the junction with Brown Hart Gardens close to Bond Street station, just after 17:35hrs on Saturday, 4 January.

He was in his car with his 13-year-old son when the suspects pulled up beside them. The pillion rider brandished a rambo-style knife, held it to the son’s throat and demanded property.

The victim complied. The suspects made off west along Brown Hart Gardens towards Park Lane, having stolen a Richard Mille watch, a Rolex watch and a diamond ring.

Both suspects were wearing a crash helmet, and spoke with a local accent. The pillion passenger was said to be of stocky build, aged in his 20s or early 30s, and wearing a puffer jacket.

There have been no arrests. Enquiries continue.

Detective Sergeant Andy Swindells, of the Westminster robbery squad and leading the investigation, said:

“This was a terrifying robbery where the suspects threatened serious violence and held a knife to the victim’s young son. Several items were stolen which had high sentimental value for the victim.

“This is very much a live investigation, and we are in the process of following up lines of enquiry, including obtaining and analysing any available CCTV footage.

“This happened just off a busy high street, at a time when there would have been lots of people in and around the West End.

“It may be that you were saw the moped make off immediately after the robbery, or you were driving through central London at this time and might have dashcam footage that could assist the investigation. We would urge you to get in touch right away.”

If you have any information about this incident, call the Westminster Robbery Squad on-call mobile on 07776244676 quoting CAD 005934/04JAN20, the non-emergency 101 number, or 999 in an emergency.

Alternatively, call independent charity Crimestoppers on 0800 555 111 if you want to remain anonymous.