People wanting to enter politics should wait until they are 45, a junior minister has suggested, making David Cameron too young to govern.
Public health minister Anne Milton, 55, said this was because it was only at that age you "know stuff".
"I think going into politics later in life is a good thing," she told a nursing union conference.
The PM, Deputy Prime Minister Nick Clegg and Chancellor George Osborne are all under 45.
Ms Milton, a former nurse who worked in the NHS for 25 years, was speaking at the Royal College of Nursing conference in Liverpool.
She was asked about moving from the NHS into government, when she said: "Would I recommend this path to anyone else? Yes, definitely. I think going into politics later in life is a good thing.
"I've gained enormously from the experience I've had in the NHS both as an RCN steward and also particularly as a district nurse.
"I think it helps, it gives you an insight and a breadth and depth so I would recommend it.
"But if anybody's got political aspirations can I recommend you wait till you're over 45. You sort of know stuff when you're over 45."
Mr Cameron is 44, although he turns 45 later this year. He became the youngest prime minister since Robert Banks Jenkinson in 1812 when he came to power last year and was six months younger than Tony Blair was when he took power in 1997.
Mr Clegg is also 44 and is just a few months younger, while Mr Osborne is 39.
Ms Milton's boss, Health Secretary Andrew Lansley, is 54, although he was under 45 when he got into politics.