One in seven firms can barely cover their interest payments and are at risk of going under if rates go up, amounting to an estimated 432,082 firms, the study found.
That is a rise of 16 per cent since 2010, and means 78,415 real estate and property services firms are at risk if interest rates rise.
The next biggest group of zombies is support services businesses, where 25,415 can barely pay the interest on their debts.
“These corporate zombies have clung onto life over the last six years due to a low interest rate environment and increased creditor forbearance, but this benign climate will not continue forever,” said Julie Palmer, partner at Begbies Traynor.
“As unemployment falls fast, under Bank of England rules interest rates could rise as early as 2014. Even if they go up by only 0.5 per cent insolvencies could increase sharply.”