From Kew Safer Neighbourhood Team:
We have had information that a number of vehicles have been broken in to with no damage. A resident has contacted us regarding a “jammer” type item (see here). Apparently this can interfere with car locking and alarms up to a range of about 300 feet. We haven’t any evidence or information that they are being used but it is something to be aware of as it is small .
Vehicles that have been broken in to have had items left them in , please ensure no items at all are left in vehicles as items as obscure as binoculars and rackets have been stolen.
Do not hide anything in boots or under seats as the suspects are able to locate these.
Linked to this has been numerous reports of people on mopeds looking in to vehicles, often with number plates concealed and faces covered, if you see this please dial 999 at the time.