Coupling up can deliver a boost to your finances, finds the report. To cover all regular payments like bills and rent, a person living alone has to spend £12,114. A second householder only brings costs to £13,435, paid for, usually, by two salaries.

A new baby would bring £1,615 a year alone in energy bills, food and rent. Those choosing to send children to private school are looking at an average annual hit of £13,194 per child.

The survey showed that rent increases from an average of £840 for a one-bedroom house; this increases to £962 on average once a second bedroom is added. Child benefit of £20.70 a week for the first child pays for only 17% of the difference.  For those choosing to buy, the average cost of a house can range from £168,000 for a one-bedroom house to £585,500 if you’re buying bedrooms for four children.

Children also add to energy and water bills, by an average of £212 a year. Starting at 2,480 kWh for a single person (about £328 a year in bills), an average electricity bill can rise to as much as £635 a year for a three-person household. And they need feeding. The average weekly food shop for a couple and their child is £42.70, as opposed to £37.20 for a couple.

Kevin Pratt, consumer affairs expert at MoneySuperMarket, said: “Starting or expanding a family is a huge step in all sorts of ways, and it’s crucial not to under-estimate the impact on household finances. Those with children on the way already know they’ll be paying for clothes and equipment for the little ones, but they may not fully appreciate how their routine bills will be affected.

“That’s why they need to make a cool assessment of how their outgoings will be shaped by a larger household so that they can take control of their finances, make savings wherever possible, and free-up budget to spend on the things they need and want for their family.”