Anlaysis by Shelter shows a family need on average a monthly income of £3,500 to afford a two-bed rental home in London

Families need to earn at least £52,000 a year to afford to rent a two-bed home in London, according to housing charity Shelter.

The charity's Homes for London campaign analysed the cost of renting across the capital and found that a family would need to take home an average of almost £3,500 a month including benefits, equivalent to a yearly pre-tax salary of £52,000. But in eight London boroughs including Hackney and Tower Hamlets they would need to earn more than £60,000 a year.

The number of families renting from private landlords in London has increased by 70% to almost one-in-four households in the past two years. In 2011 rents rose in the city by 7%, almost double the rate of salary inflation for the average London wage.

With the typical London household income less than £35,000, the charity is warning that growing numbers of families are at crisis point, paying up to half of their income in rent each month as they struggle to continue living and working in the capital.

The charity based affordability on previous research which considered that households spending more than 35% of their income on rent were likely to struggle financially.

In an Ipsos Mori poll released last week, Londoners said the single most important policy the mayoral candidates have discussed is finding a way to reduce the cost of private renting.

The Homes for London campaign is demanding the next mayor use his or her influence to make housing a top priority, and to stand up for London's tenants by brokering a better deal for them which protects families from the capital's rental market.

Shelter chief executive Campbell Robb said: "With so many Londoners locked out of homeownership, more and more families have no other option but to rent – but rents are now so out of touch with wages that some families are spending over half of their income just to keep a roof over their head, leaving little left for food, fuel and other essentials."

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