The standard of dwellings is judged against different criteria across the UK. In England, Scotland and Wales, the proportion of non-decent homes has decreased in the last 10 years.
In England, the percentage of non-decent homes has fallen to 19% in 2015 from 34% in 2006, when the current Decent Homes Standard was introduced.
In Scotland, 45% of dwellings failed to meet the Scottish Housing Quality Standard in 2016 compared with 75% in 2005. All homes are measured against this standard but the target to meet it by 2015 applies only to social housing.
In Wales the figures are based on social housing only with 14% of such homes having failed to meet the Welsh Housing Quality Standard in 2016/17. This was a decrease from 58% in 2011/12, a year before the requirement for social landlords to adopt the initial standard. The current Welsh Housing Quality Standard requires all social landlords to improve their housing stock to an acceptable level by 2020.
Link to source: Tenure trends and cross tenure analysis
In England, about 3% of households live in overcrowded accommodation. Overcrowding is much more prevalent among lower-income households, affecting 7% of people in the poorest fifth of households compared with less than 0.5% of those in the richest fifth, and around 3% of those in the middle fifth.
Link to source: CHS results
In Northern Ireland, 2% of households live in overcrowded housing. Overcrowding is less prevalent among the lowest income households, affecting less than 1% of people in the poorest fifth compared with more than 2% of those in the middle fifth.
Link to source: Scottish Household Survey
In Scotland, just under 3% of households live in overcrowded accommodation. Overcrowding is more prevalent among lower-income households, affecting 4% of people in the poorest fifth compared with less than 2% of those in the richest fifth and around 3% of those in the middle fifth.
The date of the latest data varies between parts of the UK but, in each case, a much higher percentage of households in rented accommodation lived in overcrowded housing than was the case for home-owner households.
The largest percentage point gap was in England where 7% of social renters and 5% of private renters were in overcrowded housing compared with just over 1% of home-owners. In Wales social renters were also more likely to be in overcrowded housing than private renters (6% compared with 5%) but in Scotland and Northern Ireland the proportions were similar for both renting types (4% and 3% respectively). Between 1% and 2% of home-owners were in overcrowded housing in all four parts of the UK.