The data relates only to affordable homes funded by the HCA and compares to 57,648 affordable homes started in 2010/11 and 64,692 in 2009/10.
The government argues that a change in house building programme in 2011 can explain the results and argues it is on track to meet its target of building 170,000 homes over the parliament.
Housing completions also fell to 59,541 from 64,277 in 2010/11 and 56.159 in 2009/10.
The figures did show a major uplift in the six months between October and March to 17,858 compared to a mere 2,109 in the first six months.
The last time housing minister Grant Shapps debated the 95.5% six monthly drop in the HCA figures he was involved a heated exchange on the BBC Today programme.
Despite both figures being well below half of previous years’ totals Shapps seized on the umbers hailing a rapid and dramatic progress.
He says: “Far from the predictions of the doom merchants, today’s figures show work has started on over 15,000 new affordable homes since last September – a massive increase on the previous six month period. This is clear evidence that our efforts to get Britain building are starting to yield impressive results.
Pat Ritchie, chairman of the HCA, says the numbers are a solid platform on which to build.
He says: “It also shows we are making a significant impact on boosting the supply of affordable homes in the areas where they are most needed, in partnership with local authorities and providers across England.”
The data was released just a day after shadow housing minister Jack Dromey wrote to the UK Statistics Authority to accuse Shapps of misusing data, confusing the public and obstructing public debate.