Enterprise Inns has hit back at the GMB in the row over pub closures, saying many of the trade union's assertions are "inaccurate" and "highly misleading".
The GMB last week issued figures showing that 1,131 outlets, owned by seven pub companies, had closed since December 2005, suggesting the pubco model was adding to the rate of closures.
Paul Kenny, general secretary of the GMB, which has nearly 600,000 members, also claimed some pubcos were "overcharging" licensees by up to 80p a pint to pay off their interest charges.
But Enterprise has responded saying that the closure rate among the seven pubcos is less than a third of overall closures.
A statement said: "This is hard evidence that the tied pub model has served to support pubs, especially in these difficult times, not to accelerate their closures as claimed by the GMB.
It added: "At Enterprise Inns, we are proud to support our licensees during these difficult economic times.
"In the 18 months to September 2008, over 1,800 pubs received financial assistance in the form of discounts and/or rent concessions, at a cost to the company of around £12m.
Enterprise said that since last September it had spent on average £1.4m per month in helping its tenants.
The company also said GMB's claim that "some pubcos are "overcharging" licensees by up to 80p a pint ignores two factors: the difference in rents paid by tied tenants compared to those free-of-tie; and the other benefits that tied tenants get, such as financial and business assistance.
The British Beer & Pub Association argues the "driving force" behind closures is the continuing tax hikes and "excessive regulation".