Dozens more homes were created from commercial buildings under controversial planning laws in Cornwall last year, figures reveal.

Permitted development rights allow offices, farm buildings and takeaway restaurants to be turned into residential properties without planning permission.

Homelessness charity Shelter says the rules let developers "side-step" regulations to avoid building affordable homes.

In 2018-19, 70 commercial conversions sprang up in the area, the latest Ministry of Housing, Communities and Local Government statistics show – up from 43 the year before.

Offices were the most common source of houses – 47 (67 per cent) were created from them.

Overall, commercial conversions accounted for two per cent of new homes created in Cornwall last year.

For certain changes of use under permitted development, developers must get "prior approval" for technical aspects of the plans.

But critics argue the process does not receive the same level of scrutiny as a full planning application.

Polly Neate, chief executive of Shelter, said: "Permitted development rights give developers free rein to convert office blocks into homes and allows them to side-step local planning rules.

"Not only are the homes created often cramped, poor-quality and in dangerous locations, there's also no requirement for developers to provide their fair share of affordable housing.

"With the housing emergency getting ever more desperate, it's incredibly worrying that more councils are having to resort using these converted office blocks as temporary accommodation for the growing number of homeless families turning to them for help.

"It's high time the Government prioritised building high-quality and secure social homes, instead of relying on dubious schemes that are failing to deliver the homes that local people actually need and want to live in."

Across England, more than 14,000 homes were created through conversions under permitted development rights last year – six per cent of all new homes.

The Local Government Association said the regulations have resulted in the potential loss of thousands of affordable homes.

A spokesman said: "Councils are committed to building the homes the country desperately needs, however it is vital the planning process is allowed to do its job, by making sure that homes are built in the right places, are affordable to those who need them and supported by the right infrastructure."

It was "vital" to include councils and communities in this process, he added.