I would like to find out how many households are there in each postcode in the uk. How many are there in SW15, E14
You have asked how many households there are in each postcode in the UK.
This information is currently been processed and Postcode estimates by sex and household will be available from the 2011 Census for England and Wales in the second release of statistics from November of this year to February 2013. The examples you quoted, SW15, E14, are postcode districts rather than postcodes and so hopefully the estimates at the lower postcode level will be more than suitable for your purpose.
However ONS is only responsible for the census in England and Wales. The Northern Ireland Statistics and Research Agency is responsible for the census in Northern Ireland and National Records of Scotland is responsible for the census in Scotland. Although ONS will be responsible for disseminating some UK census statistics in due course, these will not be at postcode level.
More information about plans for the release of 2011 Census statistics and links to Northern Ireland and Scotland census websites are available from the following links
You may also be interested in our 2011 Census, Population and Household Estimates for England and Wales where Census have published various tables for households at local authourity level at: