Overarching powers for school improvement partners designed to put headteachers under more scrutiny will come into force next year, the Government has announced.
Significant changes mean that Sips will assess all aspects of work at primaries and secondaries, not just educational attainment.
They will also be given the power to sign off improvement plans at weaker schools, which are needed to secure full funding. The National College, soon to be responsible for Sips, said this would make the plans "ambitious and realistic".
Improvement partners will also receive more training, and only be paired with the type of schools they are used to working in. They will set targets for everything covered by the Every Child Matters agenda, rather than just results, which is too "narrow" according to the National College.
They will also make recommendations about specialist schools' status and act as a "broker" to help teachers buy in support services. Sips will be the "main agent" between local authorities and schools, and councils have been ordered to stop employing other link advisers to work alongside them.
Teaching unions said the changes had the potential to make Sips more useful, but warned that the enhanced role could appear punitive to schools.
Teaching union the NAHT is largely in favour of the changes, but objects to the power improvement partners will have over school funding.
Mick Brookes, general secretary of the union, said: "Many heads perceive the role as just sitting in an office crunching numbers and a complete waste of time for both parties, when what they are looking for is someone who can help promote strong leadership and management.
"Two things are essential for school improvement partners to work, and these changes are a step in the right direction. The partner needs to be someone who works alongside the head rather than giving them a hard time.
"They also have to have the relevant experience, particularly in primary schools. But it is important the new role is properly balanced."
Aspect, the main union for school improvement staff, also supports the proposals.
"Teachers may see this as punitive, but it means Sips will be more accountable and better trained," said general secretary John Chowcat.
"School improvement partners will be able to help schools get high quality support, and get the best use of public money. It will help them be as effective and professional as possible. If we had any concerns, they would be that this doesn't go far enough."
John Dunford, general secretary of the Association of School and College Leaders, was pleased the changes will mean the end of local authority link advisers.
"We think around 70 per cent of Sips now have school leadership experience, and want this figure to increase," he said.
"For too long they have been expected to deliver top-down targets imposed by the National Strategies and the Department for Children, Schools and Families, and we would like to see more flexibility."
- School improvement partners were first introduced to secondaries in 2005 and primaries in January 2008. Their role is to challenge and support heads, and they are meant to streamline schools' dealings with local and central government, so that heads can have "a single conversation" about raising standards.
- Under the new plans Sips will have to be accredited and licensed to practice. A national register will be kept so Sips can be matched with the most suitable school according to their experience.
- Governors and headteachers will have "greater involvement" in the choice of their Sip.