Andrew Large, director of Clowns Day Nurseries in Derbyshire, said his settings faced a rise from £120 this year to £450 by 2010 and that it was 'just one more example of an unrealistic pressure placed on an already struggling sector'.
Mr Large said, 'It is a safeguarding issue, because it will lead to more unregistered settings being available to parents and some people may not register and carry on doing their childcare until they get caught by Ofsted.'
As Government consultation on the controversial fee proposals drew to a close, there was a chorus of condemnation from early years and childcare organisations.
The National Childminding Association revealed that there had been 1,500 responses from its members to the consultation. Director of communications Andrew Fletcher said, 'This fee increase has the potential to undermine the sustainability of many childminding businesses and will represent a significant financial burden that may cause a number to close.'
Besides the rise to £450 for daycare providers, by 2010 out-of-school provision will have to pay £400 and childminders will have to stump up £100 - both currently are charged just £20.
Steve Alexander, chief executive of the Pre-school Learning Alliance, said the increases could be the 'final straw' for some providers. He added, 'The seeming lack of understanding of current sustainability issues demonstrated by these proposed rises is extremely disappointing.'
Carol Imms, an Alliance member and administrator of the Mill Lane pre-school in Broxbourne, Hertfordshire, said the increase was 'catastrophic' for sessional provision like hers, which already has to raise between £4,000 and £5,000 a year just to keep going.
The National Day Nurseries Association said its members were worried about how to bear the costs without raising fees for parents. While recognising that the subsidy has not 'disappeared', the NDNA questioned the effectiveness of local targeting and said stringent guidance and ring-fencing would be required.
Anne Longfield, chief executive of the charity 4 Children, said the proposed fee rises 'threaten to put settings, in particular the smaller ones, at risk of closure'. She added, 'If the fee increases are inevitable, while hoping for another way, 4Children feels that settings would be better equipped to cope with the introduction of gradual increases over a longer period of time, and need assurances that funds generated will be directed towards training for inspectors and reinvestment into improving outcomes.'