Ex-Liberal Democrat leader Sir Menzies Campbell was a victim of "endemic ageism", experts have said.
John Peel, a consultant with employment law experts Employersafe, said that, according to the law, people should be judged on their performance, not their age.
"I think it is pretty clear to most people that Sir Menzies has been impeded because of his age," he remarked. "[This] is a sad reflection on the treatment of older members of society and shows just how endemic the problem of ageism is."
Sir Menzies, who is 66 years-old, told the BBC yesterday that he could not get out from under the "cloying blanket" of questions about his age.
Peel added that he found it worrying that, following Sir Menzies' resignation, the focus had now shifted to finding a younger replacement.
"If employers acted in such a shameless ageist way, they would be flouting the law," he said.
However, HR Zone member Keith Luxon said: "Isn't the real reason he is going is that he is the leader of an organisation that failed to deliver its core purpose - electoral success?"
HR Zone recently reported that 16 million workers have claimed to have witnessed ageist behaviour in the workplace in the last 12 months.