In an interview with Third Sector this week, Leather cited the "clear difficulties we have over resourcing" as the biggest disappointment of her 18 months at the organisation so far.
The Government has cut the commission's funding by 5 per cent each year for three years, despite giving it a raft of new responsibilities in the Charities Act.
"It does mean we are having to cut some valuable activity and change the way we do things," said Leather.
"An organisation such as the Charity Commission is its staff, and I'm acutely aware that the financial difficulties are affecting them."
She also defended herself against criticism about her membership of the Labour Party. "It's easy to lose sight of the fact that we all have multiple identities and allegiances," she said. "If people see only one thing, they make blinkered and narrow assumptions about what a person is like."