Boris Johnson's sister stayed with a poor Deptford family for a BBC documentary and proclaimed afterwards "they are living like animals".

Rachel Johnson, an Oxford graduate who was privately educated and once edited posh mag The Lady, stayed with the family, whose budget was just over £1 a day.

It was for Sport Relief programme Famous, Rich And Hungry, which airs on BBC One on March 12.

Afterwards she told the Radio Times she once assumed poor people spent all their money on cigarettes, booze and TV.

But she said: "The poor people you see on the box are all fat. How, in God’s name, can you be overweight and hungry? Now I know."

She said: "There’s this terrible sense of human waste. They’re existing, rather than living, like battery hens. Apart from the telly and the cigarettes, they are living like animals.

"I realised, with a terrible thud, how much money I’ve wasted. I can’t pay £3 for a flat white coffee without thinking: ‘That’s a day’s food for a poor family'."