Lose a laptop or mobile phone on a train from Fenchurch Street and sooner or later a police dog will be sniffing around it, careless passengers are warned.

Rail bosses at National Express C2C are handing any familiar items left on trains through East London to Essex over to British Transport Police if they’re unclaimed after three months.

The common items are being used for the police dog-training programme looking for drugs and explosives.

“The dogs become acclimatised to the type of objects they will come across every day,” explained dog handler Pc Steve Madden. “That way, they’re not fazed when faced with them at work such as broken laptops, mobile phones, old clothing, bags and suitcases.

“Everything is used to train our dogs in the most realistic way possible.”

The unclaimed ‘leftovers’ from C2C’s Fenchurch Street lost property office are used to train animals to seek out drugs, explosives and cash which can be hidden in items of personal property.