He urged recruiters not to "give up" on any talent, as they could be the organisation's next supplier, customer or future hire.
Thompson was speaking yesterday at the CIPD Annual Conference in Manchester. He talked about how Barclays has changed its approach to talent management and youth employment.
Thompson said Barclays own war for talent ended 18 months ago with the appointment of CEO Anthony Jenkins, who took over from Bob Diamond in 2012. He said one of Jenkins first aims was to try and tackle the UK's high levels of youth unemployment.
"When [Jenkins] took over as CEO he said he wanted a complete culture change at the company, as we had lost touch with what young people want," said Thompson.
"At Barclays 18 months ago we had an extremely high turnover rate, and we were losing 60-70% of call centre staff every year," he said. "The company also had fewer than 200 employees aged under 21 and not one under 18, driven by this phoney war for talent."
"The way banking is going - where customers can do it all in the palm of their hand - it's important our employees are digital natives," he said.
Thompson also called for employers to change the way they look for new talent and not include the barrier of "5 GCSE A-C grades".
"There is too much emphasis put on academic qualifications and not on what fits business values and purpose," he said.
"UK PLC needs to re-define what talent is, and also re-define its HR practices to support young talent."
