Their findings are published today in a report which says that South Lanarkshire schools consistently provided 'a very high quality of education.'
They also interviewed councillors, met teachers and other school staff, talked to chairs of school boards, parents, pupils, Youth Council representatives, attended dozens of meetings dealing with the delivery of education in South Lanarkshire as well as undertaking a large number of interviews with stakeholder groups and education staff.
Their glowing report says that the council provided 'a very high quality of educational services to children, young people and their families,' while the department of education resources was said to be 'very successful' in implementing the council's strategic policies - serving the present and future needs of those sections of society and revitalising and sustaining community life.
For council leader Eddie McAvoy, the HMI findings are an endorsement of the success of South Lanarkshire's policies to provide education of the highest standard.
Mr McAvoy said that was perhaps best summed up in the words of the report when it says: 'Serving the current and future needs of children, young people and communities was at the heart of the council's strategic policies. Elected members, the Chief Executive, the Executive Director of Education Resources and officers throughout the Council all shared an unambiguous and powerful vision of education as a force for raising people's as piration.'
And Mr McAvoy further quoted from the report: 'Evidence of the influence of the Council's vision could be observed in measurable improvements within specific schools and pre-schools centres, in flexible provision for individual children and young people and in major authority-wide developments.'
Explaining South Lanarkshire's drive to put education at the top of its agenda, Councillor McAvoy said: 'As a Council we have had one overriding objective: to provide the best education possible in each and every one of our schools.
'For instance that desire - and only that - has been the determining factor in our decisions to spend over£600 million to create South Lanarkshire primary schools and secondary schools designed to meet the needs of the 21st century.
'We recognised that a crucial element in giving our children the best start in life was the opportunity for them to learn in surroundings where they can fulfil their full potential - where their chances of success can be enhanced and improved.
'And that is why we set in place policies that put children's education at the top of our agenda and have boosted the cash going into our classrooms by millions of pounds each year for eight years, opening the doors to many progressive and well-received initiatives.
'So it is gratifying that the HMI report recognises the work that we have been doing, and on which we will continue to build.'
Mr McAvoy said it was also pleasing to note the recognition the report pays to the outstanding work of executive director of education resources Maggi Allan and her management team and staff in education's central services - and to South Lanarkshire's teachers and those who support them in the area's schools.
'For them, this report is not just pleasant reading, it is a recognition of their sheer professionalism and their driving desire to see the children and young people of South Lanarkshire succeed.'
Indeed the Inspectorate was particularly impressed by the v ery strong and effective leadership of education provided by Maggi Allan.
Given the 'very clear direction' provided by elected members and the council's chief executive, Michael Docherty, the inspectorate felt that Maggi Allan's 'incisive understanding of the key priorities and her determination that all decisions should consider the long-term interests of children and young people were succeeding in bringing about a number of creative responses to difficult strategic issues.'
The report also makes it clear that a key factor in South Lanarkshire's approach was corporate working across all departments of the council, which had been driven by elected members under the leadership of Mr McAvoy.
In fact the Inspectorate considered that the leadership of South Lanarkshire was not just 'very good', but in many respects 'outstanding'.
Indeed, the council's commitment to corporate or joint working across departments, not least the direct involvement of social workers at school level, was said to be having a significant impact of front-line services by providing effective support for troubled young people, boosting achievement and heightening the quality of the education experience of young folk in south Lanarkshire.
Looking at South Lanarkshire's educational provision and performance, the HMI report says that the council has provided a pre-school place for all three-year-old and four-year-old children whose parents wish a place. It also records that the council has opened 38 early years' establishments.
The council was committed to ensuring that pupils with special educational needs were educated, wherever possible, in their local area. This commitment was manifested in the creation of additional provision for special educational needs within mainstream primary and secondary schools.
It also details that the education budget had risen from almost£190m in 2001-2002 to£225.5m in 2003-2004 - a rise of£35.5m in just over two years.
The report notes that the percentage of pupils staying on beyond the compulsory learning age has been consistently above the national and comparator authorities averages over the past three years.
It also say that the percentage of schools leavers entering full-time higher education from 2001 to 2003 had been considerably above the national and comparator authority averages, and that in the same period the percentage of school leavers entering employment had been above the comparator averages.
Looking at 5 to 14 performance in primary schools, the report says that between 2000 and 2003, South Lanarkshire's figures for reading, writing and mathematics had remained consistently better in all three areas than the national average and other comparator authorities.
In reading and mathematics, performance was between 3% and 8% above comparator and national averages. In writing, it was between 1% and 6% above these figures, with the council's ambitious targets set for attainment in reading, writing and mathematics being exceeded.
In secondary schools, between 1999 and 2003, in reading, writing and mathematics the percentage of S2 pupils attaining appropriate national levels of attainment in South Lanarkshire was higher that both national and comparator averages for all four years.
Performance was between 1% and 7% above both comparator and national averages in reading and writing.
It was between 4% and 9% above national averages in mathematics, and 7% and 13% above comparator authorities.
Looking at how South Lanarkshire supports out-of-school learning, the HMI report says: 'Education Resources was very effective in supporting pupils' achievements through a well-balanced range of out-of-school hours learning activities, including breakfast clubs and supported study activities.'
In its conclusions, the HMI report says that standards of attainment in South Lanarkshire's primary schools were high, that there was very positive performance at S1/S2, and that SQA performance by the end of S4 and S5 had been improving in line with national and comparator averages, while rates of improvement in some measures of performance by the end of S6 were above the averages.
The challenge now facing the authority was to build on its achievements.
'Overall, South Lanarkshire Council was a very effective education authority,' says the report.
It was an authority which 'was adding considerable value to the work of its educational establishments???and was making very good progress in implementing its broad and inclusive vision and in responding to the National Priorities in Education.'
And the report concludes by saying that South Lanarkshire was 'well placed to ensure that the gains in pupils' achievements were sustained and built on at all levels.'
Listing South Lanarkshire's key strengths in the delivery of education, the report records these as:
* The clear vision and inspirational leadership of the executive director and heads of service;
* The prominent roles played by elected members, the chief executive and officers of the council in promoting a broad approach to supporting the learning of children and young people, and celebrating their achievements;
* The effectiveness of education resources in working with corporate services and other agencies to provide more integrated support to children, young people, families and the community;
* The effectiveness of managers and staff in central services, their very good teamwork and the high quality of their support to establishments;
* The quality of financial monitoring and control;
* The well-established approaches to quality management and systematic performance monitoring;
* Innovative and well-run initiatives resulting in improvements in the learning, experience and achievement of children and young people, and in the quality of services to stakeholders generally;
* The high levels of achievement in primary schools, and the success of these schools in reducing levels of exclusion.
And lis ting some three recommendations, the report says that South Lanarkshire should:
* Develop further its very effective approaches to performance monitoring and evaluation; should build on its well-founded improvement framework to further improve the attainment and achievement of pupils, and should ensure that special need schools provide an appropriate length of week for pupils [ matching the length of the school week in mainstream schools].
As Scotland's fifth largest local authority, South Lanarkshire is responsible for the education of around 46,000 children and young people at 124 primary schools, one of which provides Gaelic medium education, 21 secondary schools one also providing Gaelic medium education, nine special schools. Pre-school education is provided in 77 early years establishments, including two nursery schools, 60 nursery classes in schools, 15 community nurseries as well as in partnership with 55 centres. There are also ten Universal Connections centres as part of the wider range of learning programmes for young people. In addition, South Lanarkshire's Education Resources is responsible for 25 public libraries and five mobile library services and home delivery services.
In determining their 'scoring', HMI Inspectorate use 11 quality indicators, each of which is rated on a four point scale: very good; good; fair; and unsatisfactory. South Lanarkshire was rated 'very good' in ten of the indicators and 'good' in one.
The report is the best to be published in Scotland so far.