Record numbers of children are being placed in unregulated housing by Norfolk and Suffolk councils, amid national concerns about their vulnerability to criminals.

A BBC Newsnight report called Britain's Hidden Children's Homes, broadcast on Monday night, found 5,000 children in care are now living in unregulated accommodation, up 70pc in the past decade.

The children are placed in the homes by councils to encourage them to live independently.

They have support workers either living on the site or paying visits, but are not subject to the same inspections as regular children's homes.

An investigation by this newspaper in 2017 revealed the squalid state of some of the unregulated accommodation which Norfolk County Council was paying a private firm millions of pounds to provide.

In response the council spent £5m setting up its own homes for teenagers leaving care, but it still uses unregulated accommodation.

Figures obtained by Newsnight show the council has spent more than £9m on this type of accommodation since May 2015.

The number of children in Norfolk living in these homes rose from 14 in 2009 to 68 in 2014. It fell to 56 last year.

In Suffolk the number of children has more than quadrupled from 24 in 2009 to 113 in 2018.

Director of Norfolk children's services, Sara Tough, said: "Finding the right accommodation to support care leavers into adulthood can be challenging because young people who have been in care can have a range of complex needs.

"For this reason, we have invested £5m in providing our own accommodation for young people, with dedicated round-the-clock support. This is in addition to placements offered by the voluntary and private sector, which we monitor regularly."

Chair of the All Party Parliamentary Group for Missing Children and Adults, Ann Coffey MP, said nationally their research showed a "twilight world of homes that have become a magnet for paedophiles and drug gangs".

"Children are being dumped miles away from home in unregulated accommodation […] to fend for themselves and take their chances with what can be a very brutal and exploitative world," she said.

Cambridgeshire Police told the MP: "These premises are often well known to local criminals and are seen as an easy target location for recruitment of new children."