Around 10,000 disabled people are set to receive more generous benefits after winning a legal challenge against the government.
They stand to gain an extra £70 to £90 a week after defeating the Conservative government at the Upper Tribunal.
Rules on Personal Independence Payments (PIP) will now have to be re-written.
Previously rules governing PIP said people could carry out tasks unsupervised if it was "unlikely" they would come to harm.
But judges at the Upper Tribunal, which has equal status to the High Court, said the the Department for Work and Pensions (DWP) should make its decision on how serious the potential harm could be, rather than the likelihood of it happening.
People with epilepsy warned the tribunal that the chances of them suffering a seizure on the job were unlikely but had catastrophic consequences if they did.
Epilepsy Action chief executive Philip Lee told the Mirror : "Many people with the condition could have a seizure at any time, often without warning.
"We know the current system is not working and is failing people with epilepsy. They are more likely to be refused PIP than those with any other health condition."
Disabilities minister Penny Mordaunt said: "These updates will help us continue to ensure people with the highest costs associated with their disability or health condition are receiving the most support."
But the minister has risked fury by describing the tribunal as a "binding" legal judgement and deciding to follow it.
Labour Shadow Work and Pensions Secretary Debbie Abrahams said: "While we welcome any increase in support for those who need PIP, this is a drop in the ocean of the funding that the courts have ruled should rightfully go to recipients.
"The government must immediately act on all of the court judgements on PIP."