Farmers who use neonicotinoids are hoping that trials will show that the risks to bees have been overstated

Research blaming pesticides for the decline in honeybees has been called into question by a leaked note suggesting that scientists had decided in advance to seek evidence supporting a ban on the chemicals.

The private note records a discussion in 2010 between four scientists about how to persuade regulators to ban neonicotinoid pesticides.

The EU imposed a temporary ban last year after the European Food Safety Authority identified risks to bees. The Department for Environment, Food and Rural Affairs opposed the ban, saying that there was not enough evidence of harm to bees.

Many farmers have blamed the ban for high levels of damage to this winter’s oilseed rape crop from flea beetle.

The leaked note says that the scientists agreed to select authors