Residents in Frognal and Fitzjohns are being warned to protect their post after fresh reports of mail theft and fraud.

Police said fraudsters have been using the stolen mail to acquire bank cards and take “loads of cash”.

Pc Edward Bromilow, of the Frognal and Fitzjohns neighbourhood policing team, said prevention is “a bit tricky” and expensive – but stressed options are available.

“A secure, lockable postbox behind a locked communal door is a good way to go as it adds two barriers for a thief to have to beat,” Pc Bromilow said, adding that the majority of thefts are from external postboxes.

“Fitting a brush or a flap to your postbox, so it’s much harder for someone to stick their hand in and retrieve any post, is a good idea, as is getting CCTV coverage.”

Pc Bromilow said residents should also challenge people in their buildings they do not recognise, collect post regularly and consider picking up bank cards from a branch instead of having them sent in the post.

But the “gold standard”, he added, was to have post come through a front door rather than to a separate box in a lobby.

The warning comes after two incidents of mail theft were reported in Hampstead in early August.

The thieves tricked their way into a lobby and took post, prompting police to tell residents not to buzz in anyone without first verifying their identity.

Anyone who has experienced mail theft should call police on 101. Residents are also advised to speak to their bank if someone in their street or building has been a victim of mail theft so any unusual banking activity can be monitored.