Scotland Yard wants to monitor Britain’s power network so it can locate cannabis farms, The Times has learnt.

Officers hope to investigate spikes in electricity usage that could be caused by production of the Class B drug on housing estates and in industrial areas.

The move comes amid concern that half a million people are secretly growing cannabis in their homes. Already more than 650 cannabis farms are discovered every month across England and Wales, and the numbers have grown steadily over the past decade.

The Metropolitan Police drew up plans last year to remotely monitor the electricity network to locate cannabis farms, but the project failed to get any further when a bid for Home Office Innovation Funding was turned down.

Now, an anti-theft