Jonathan Evans, the director-general of MI5, said he's concerned the agency is being held back by older agents who don't understand the world of computer technology.
"I think some of the staff perhaps aren't quite the ones that we will want for the future," Evans recently told Parliament's Intelligence and Security Committee.
Evans did not say how many are being laid off, The Daily Telegraph reported Monday, noting MI5 is in the middle of an overall expansion plan.
MI5 has about 3,500 agents and plans to have is 4,100 by next year, double the number in 2001. Many of the new agents are in their 20s and 30s.