"Inspectors assessed teaching quality at our school as very high yet with the money we have allocated half our eligible teachers would miss out."
Tim Andrew, head of Chesham high school in Buckinghamshire, said: "I strongly support industrial action. The issue is not performance-related pay, but the lack of funding. I face a pound;30,000 shortfall in the money I would need to give performance-related pay to teachers. How could I find that money: by cutting back on support staff, or losing a teacher and increasing class sizes? It would damage my school."
Phil Tailor, head of Stamford community high school in Ashton-under-Lyne, Lancashire, said: "I definitely support industrial action. Heads have been placed in an impossible situation because the expectations of teachers have been raised and the funding is not there to meet them."
"I would have to disappoint at least 10 people who have reached the standard because I don't have the funds for everyone."
Ann Mullin, head of Highbury Fields school in north London, said: "The system is unworkable so I will be supporting industrial action. The Government is putting heads in the line of fire. I'm going to be the one facing grievance procedures from my staff."
Barbara Merrick, head of The Middlecott school in Kirton, Lincolnshire, said: "For the first time I am giving serious consideration to industrial action. I'm very unhappy and dissatisfied with the way the scheme is going to work. I wouldn't be able to give money to all the staff who deserved it and would have to pick some over others - which would cause problems for staff morale."