Your statement, "Government rules require associations to set their rents in line with the retail price index of inflation" is incorrect. Associations are required to INCREASE their rents in line with the RPI - there is a significant difference.
The Housing Corporation Circular 27-01 says:
"The rent influencing regime will continue to seek to bear down on rent INCREASES through the issue of a guideline limit for rent INCREASES and influence rent levels through the rent restructuring framework."
"the guideline limit for HA rent INCREASES will be 0.5% a year in real terms from 2002/2003 onwards."
"Over the 10-year implementation period, target rents will INCREASE by RPI+0.5% a year."
And the circular specifically deals with protection of the public and private investment in associations' stock:
"In deciding whether to challenge an HA’s rent levels, or their rate of increase, our paramount concern will be to protect the public and private investment in its stock and to retain the confidence of lenders."
Dangerous Darling and Crash Gordon have got the UK into a right mess by overspending, and borrowing beyond their means. Their build targets seem to have gone out of the window as they look to plunder the finances of the housing sector to pay off their credit card bills.
Shame on you Mr Brown.