Early achievement provided a positive experience at school, shaped attitudes towards later learning and boosted self-confidence. But Mr Osler,the Government's principal education adviser, said some children found learning more difficult.
He warned teachers: "The complacency of the past which was founded on reassuring comments to parents such as 'don't worry, he's just taking a little longer than others', or 'she'll be fine, everyone reads eventually',cannot be sustained. If children are having problems with learning the basic skills of literacy and numeracy, that must be identified and everything possible must be done to assist the child as early on as possible.
"If we do not do that, access to other aspects of learning will be barred, children's confidence will be eroded as they compare their own skills to those of their peers. It will lead to emotional and behavioural difficulties and can lead to long-term disaffection from the process of learning. It will also have a detrimental effect on the rest of the family."
He made no apology for the early intervention focus on literacy and numeracy. They were the core to lifelong learning and accessed other areas of the curriculum.
Turning to wider aspects of Government policy towards social inclusion and early intervention, Mr Osler cautioned local authorities about their sometimes questionable links with other pre-five providers and revealed his staff are to review partnership agreements this autumn. "In that review, any evidence that cost-effective opportunities for partnership have been missed will be considered carefully," he announced.
Mr Osler said: "The reason for this vigilance is simple: it is because parents value a diversity of services. The needs of families vary. Some parents will be happy with one session of pre-school education each day but many work full-time and many more want to return to work or education. For them, all-through provision of education and care, preferably in one place, is essential. "
Councils should not ignore private nurseries and playgroups if they provided a better service.
But the senior chief inspector re-emphasised that there should be no diminution of standards and pledged every private and voluntary centre receiving grants would be inspected by the end of this year. Ministers were shortly to announce an early years best practice initiative and would continue to set national standards for pre-school education. Curriculum guidelines for three to five-year-olds were also being developed.
Mr Osler said: "Without a high level of quality, these policies are pointless and may even be harmful." He also suggested the Scottish parliament would be forced eventually to amend children's legislation to integrate services.
At present, councils would have to submit pre-school plans alongside children's services plans. Further guidance on "joined-up" government would be available soon.