Families' incomes have recovered to their strongest levels in at least three years - but the gap between the "haves" and "have nots" is growing - a report has found.
The average monthly income of a UK family reached £2,166 in December, marking the highest figure seen since Aviva's regular family finances report started in 2011 and following 18 months of steady increases.
Family incomes have risen by 12% since January 2011 when the typical family took home £1,937 a month.
But despite the overall improvement, families are now separated by a bigger income gap than in January 2011, the report found.
Three years ago the difference between average monthly incomes of the highest and lowest earning types of family was £1,281. That gap has increased by 14% to £1,459 in December 2013.
Those with the highest average incomes this month are couples with plans to have children, who take home £2,422 typically. Single parents with one child or more have the lowest typical income at £963.
Researchers also found that couples with no plans for children take home £2,284 a month on average, couples with one child bring in around £2,321, those with two or more children have £2,301 typically and families where the parent is divorced, separated or widowed with one child or more take home £1,189 on average.
Families' changing fortunes mean that couples with one child have gained the most over the last three years and have seen their monthly incomes grow by 18%.
Their gains are in stark contrast to divorced, separated or widowed parents who have seen their monthly incomes fall by 14% over the same period, the report found.
High living costs also appear to have worn away at family savings over the last year. Some 30% of families said they have less than £500 put away, compared with just 14% in January 2013.
The percentage of families with less than £2,000 to fall back on has also jumped from 28% to 40% between January and December.
As the struggle to find savings accounts offering real returns on nest eggs continued, Aviva found that the uptake of tax-free Isas among UK families has dropped by two percentage points in the last six months alone - from 41% in July to 39% in December.
Louise Colley, protection distribution director for Aviva said: "The cost of living is uppermost in many people's minds this winter.
"Growing incomes mean some families will be starting the new year in a better financial position than they have become accustomed to in the last three years.
"But sadly the widening gap between the 'haves' and 'have nots' means this cheery outlook will not be shared by all."
More than 2,000 people who live as part of a family group were surveyed for the report's latest findings.