A principal credited with turning around one of Norfolk's failing schools is to become the chief executive of a new academies trust for the county.

Rachel de Souza will leave her post at Ormiston Victory Academy – the former Costessey High School – at the end of this academic year.

The East Norfolk Academies Trust was originally set up by academy sponsor Theodore Agnew to support Great Yarmouth Academy, which opened this year in place of Greenacre Primary School, and now plans to expand.

Mrs de Souza's Sir Isaac Newton Sixth Form Free School will also be part of the group with early talks already under way with Norfolk County Council and the Department for Education about other schools.

Mrs de Souza said: 'We are looking to grow to be a small group of schools that are aspiring to excellence and doing education in a different way.'

Mr Agnew stressed that he would be looking to include no more than six schools in total – from primary level to post-16 provision – and would get them all working together. Teachers from the sixth form would all be expected to work with primaries to raise standards. 'We want to move specialist resources around the group,' he said.

Mrs de Souza became principal for Victory Academy in September 2010 when it replaced the high school following years of under achievement and two spells of special measures.

It has since posted significant improvements in its exam results and, following an initial inspection earlier this year, was found to be making 'outstanding progress'.

The principal had been at her previous school – Barnfield West Academy – for four years.

She said her departure at the end of this year would come as no surprise to most people.

'The principal you hire to take a school from special measures is very different to that long-term job of taking it forward,' she said.

'Victory has been on a huge journey. It's gone from a failing school to a really good, sustainable one. The teaching is great and it's a good time for them to get a different type of principal.'

Mrs de Souza said she had 'every confidence' the school could continue its upward trend under a new leader insisting, 'otherwise I haven't done my job properly'.

With the support of her vice- principals, she will juggle both roles for the rest of the academic year and see Victory Academy through its first full Ofsted inspection.

The search for a new principal for Victory Academy will begin in the summer term.

Alison Thomas, county council cabinet member for children's services, said: 'We really appreciate the excellent work done by Rachel and her team at the Victory Academy, and wish her the very best on this exciting new venture.'