David Cameron's mother has signed a petition against spending cuts that would see the loss of every children's centre in his constituency.
Retired magistrate Mary Cameron, 81, put her name to a battle to save 44 children's centres due to be closed by Conservative-run Oxfordshire County Council.
Council workers in Mr Cameron's Witney constituency will stage at 24-hour strike next week in protest at the plans, with the union Unite accusing the council of "turning its back" on children, young people and their families
Mrs Cameron apparently signed the petition while she was visiting her son. She told the Daily Mirror: "My name is on the petition but I don't want to discuss this any further."
The plans will see £8 million shaved from its children's services provision, halving the budget for early years education.
The closed centres will be replaced with eight children and family centres, but these would only be accessible to the most vulnerable people by referral, campaigners said.
Jill Huish, from the Save Oxfordshire Children's Centres campaign, told the Banburyshire Info website: "I am delighted that Mary Cameron has joined the senior voices, including that of her son the Prime Minister, against the Conservative county council's closure of children's centres.
"It seems to be a bizarre situation where David Cameron is unable to defend children's centres against the cruel cuts he's allowed his own Government to impose on local authorities."
The Prime Minister wrote to the local authority in his capacity as MP for Witney last year expressing "disappointment" at planned cuts to museums, libraries and day centres for the elderly.
But council leader Ian Hudspeth hit back, saying the curbs were the result of reductions in funding from central Government.
Unite accused Mr Cameron of being "two-faced" over his criticism of the council.
Oxfordshire County Council and Mr Hudspeth refused to comment on Tuesday on Mrs Cameron's signing of the petition or the planned cuts.
The petition, which has attracted more than 7,000 signatures and is addressed to the council and its cabinet member for education, Melinda Tilley, says: "Our children's centres are a lifeline to new parents who rely on locally accessible advice and support at a time when it is most needed.
"Cutting these essential services would leave families vulnerable and isolated, and fail an entire generation of children."
It goes on: "It is a false economy to close children's centres. Universal access to the early intervention services they provide has numerous economic and other long-term benefits for the health and well-being of parents, children and the wider community."
Mr Cameron's official spokeswoman declined to say whether the Prime Minister had spoken with his mother about the anti-cuts petition, telling a Westminster media briefing: "I'm not going to get into private conversations between the PM and his family."
But the spokeswoman pointed out that the Prime Minister himself wrote to Oxfordshire County Council leader Ian Hudspeth last year to say he was "disappointed" at proposed cuts to frontline services, including elderly day centres, libraries and museums.
Mr Cameron's spokeswoman said: "The Prime Minister has talked many times about the need, as we look at how we manage our public finances better, to make sure we are making efficiencies through back office savings and therefore continue to protect the frontline and the services that local people need.
"That is something he reiterated in a letter to the leader of Oxfordshire County Council."
In response to Mr Cameron's letter, Mr Hudspeth pointed out last November that the council had already made "significant" savings totalling £626 million since 2010/11, including taking out "as much from the back office as possible".
In a letter to the PM, the Conservative council leader said that the Government had cut Oxfordshire's revenue support grant by almost 50% over five years while imposing additional duties on the authority.