Speaking on the Victoria Derbyshire show today, the MP for Islington South and Finsbury, said there are problems with people owning land then banking it, and the same issue exists for empty flats.

Thornberry [pictured] said: “If you leave a flat empty and you’re not using it, then you will lose it. They [owners] would need to justify why it’s been empty for the amount that it has.

“If you go down the Thames there are all these developments, all of these big blocks of flats and you go down there at night – none of them have their lights on; they’re all empty.”

When asked if she would take private property off owners, Thornberry said: “Yes, because they’re not being used and because we have a housing crisis, we have people living on the streets, homeless families in bed and breakfasts, it’s not right.”

The shadow defence secretary said that when it comes to empty land, local authorities should have the power to zone an area where land isn’t being, such as a brownfield site, and use it for housing.

Developers should then have five years to build affordable housing or they will lose it.

She said: “People are taking the mickey. It’s because housing prices are so high that it’s worth your while just sitting on a bit of empty land and seeing how high prices go before you build. That’s immoral.”

In July 2018 the government announced proposals to give authorities the power to triple council tax on homes left empty for five to 10 years, and quadruple it on those left vacant for more than a decade.

Councils would then be able to use the funds to keep council tax levels down for other residents.