FAMILIES are being warned to keep their doors locked, even when they are in the house, following a spate of "sneak-in" thefts.

The warning came as police revealed that of the seven or eight burglaries that take place nightly on Teesside, at least two or three occur because of unlocked doors.

In many cases, the occupants are in the house and meet the opportunist thief face-to-face.

Crime prevention sergeant Chris Garner said that many people do not realise they have been burgled until after the thief has left.

"Thieves are often confronted by the occupants, but they come up with excuses that are half plausible such as 'I thought this was my friend's house'.

"It's only after they have left that people realise it isn't true. They often find that things like handbags, small electrical items, cash and bikes have gone."

While Sgt Garner said crime prevention schemes such as postcode marking have proved successful, she said the message that doors need to be kept locked is not getting through.

"We live in a world where most people are honest and it wouldn't occur to them that people would do this," she said. "The reality is that these people are desperate for money and they have the cheek to risk being confronted."

Sgt Garner said homes where children are constantly coming in and out are particularly vulnerable.

"When people hear a noise, they assume it's the children," she said.

"If people locked their doors it would cut burglaries. Sometimes it's just a matter of asking people who they are, and not being fooled by excuses.