Equine charities claim 6,540 further horses are at risk of becoming welfare cases this winter.
But they have no more room, following years of rising equine abandonments and neglect since the start of the downturn.
Six charities, including World Horse Welfare, the RSPCA and Redwings, are predicting an equine crisis.
They handed a report to the Government on 15 October, calling for action.
Initiatives they urge the government to consider include making fly-grazing a criminal offence, more regulation of the importation and export of horses and creating better mechanisms to link neglected horses to their owners.
The RSPCA says it took in 304 horses in 2011, twice the number it did in 2010.
This news story was first published in the current issue of H&H (25 October 2012)