Goal seems to be for people ‘to lose confidence in the system’, says head of industry body after devices found in Birmingham and Leipzig

If Russia is proved to be behind an incendiary device plot that caused fires at two parcels warehouses in July, it will be evidence that Moscow is aiming to disrupt western confidence, an expert has said.

The dangerous packages, which caught light at DHL sites in Birmingham and Leipzig, are not thought to have been sophisticated but in both cases appear to have evaded security checks. German authorities warned this week that a plane could have been downed if the devices, which were both sent by air, had ignited in flight.