Economic gloom is creating a new class of bolder burglars, one of the UK's top police officers has warned.

The downturn has prompted thieves to take more risks when they search homes for cash and valuables, according to Sir Hugh Orde, Chief Constable of Northern Ireland. Orde revealed that there has been a steep rise in so-called 'creeper burglaries' across Northern Ireland in recent months where residents are in the house and often asleep.

He told the Policing Board, the body that oversees the PSNI, that burglars are going to extreme lengths because money is short. 'The areas of major concern we are still seeing are a huge number of burglaries, certainly creeper burglaries,' he said.

The chief constable warned that 45 per cent of house break-ins take place because windows and doors are left open. He said: 'We are still failing to get the message across to people to lock their doors and windows whether they are in or out.

'I know there are some cultural issues; people like to have the feeling that they do not have to lock their windows and doors. The reality is that you can prevent yourself being a victim of crime by taking some fairly basic crime prevention measures. But we will continue to put a huge effort into domestic burglary.'

Orde reported that there had been an increase in the number of 'creeper burglaries' from 50 in April to 60 in May. He argued: 'The key issues remain the same - domestic burglary, as I have touched on, creeper burglary in particular.'

He laid the blame for this increase on the economic downturn: 'The current economic trends are not looking good. Where things become more expensive, crime increases.'