The Environment Agency could be forced to check every tree on its land after a Sussex teacher was felled by a falling branch.

Doreen Prior has been unable to work since she was struck by the branch as she walked on land at Barcombe Mills, near Lewes.

She is claiming £300,000 in damages from the Environment Agency and fears she could lose her home because she cannot afford to pay the bills.

Her lawyers believe if she wins her case at the High Court it could force the agency to check each and every tree it maintains across the country to prevent further people being hurt and launching legal action.

There are no specific rules on how often safety checks should be carried out on trees but landowners are required under public liability laws to make sure all of their property is safe.

However Forestry Commission guidelines instruct landowners to check the safety of large trees at least once a year.

Ms Prior’s claim to the High Court says that if there had been a proper system of inspection of the tree prior to the accident then the poor condition of the branch would have been identified before the accident occurred.

It continues: “The branch that fell on her had no leaves or shoots and was clearly dying or dead and landowners the Environment Agency should have known to remove it.“ According to the writ, the Environment Agency has admitted to Ms Prior’s solicitors that there had not been regular checks on trees before her accident.

On the day of the accident, in April 2007, Ms Prior was walking on the public footpath through Barcombe Mill when the branch of an ash tree fell on her.

The force of the branch cut her head, but she said the knock on effects were much more serious.

Since the accident she suffers from tiredness and impaired memory as well as having difficulty planning, organising and multi-tasking, making it impossible to work as a teacher.

She fears that if she is ever able to return to work in the future, she will be disadvantaged in looking for employment because of her handicap.

Speaking from her home on the banks of the River Ouse, next to the disused corn and paper mill, Ms Prior said: “I'm just so worried this could happen to a child with all the families that come down here.

“It was right on the path.”

Ms Prior's solicitor, Laura Middleton-Guerard, said: “The Environment Agency had failed to carry out any inspection of the trees adjacent to the popular public footpath for a number of years.

“Such simple measures could have prevented the incident from occurring and such serious injuries being sustained.

“Mrs Prior was knocked unconscious and taken to Princess Royal Hospital in Haywards Heath and was later diagnosed as having suffered a head injury.

“The injuries she sustained have had a huge impact on her day to day life leaving her heavily reliant on family and friends for financial and emotional support.

“Suffering from extreme tiredness, she is still unable to return to teaching and is under great financial strain as a result.”

A spokesman for the Forestry Commission said that there were no specific rules on how often trees should be checked, other than the standard owners’ liability laws, which apply to all land owners.

But any High Court ruling could impact on millions of trees.

An Environment Agency spokeswoman said: “The case is currently with our solicitors.”