" It is not good enough and there needs to be not just fiddling changes "
In her first interview since being promoted to the cabinet, the former minister for school standards said improving education for 11 to 16 year olds would be a "main priority" for Labour's second term.
Ms Morris defended the government's decision to abandon fully comprehensive education by allowing many schools to specialise in subjects of their choice.
And in a warning to those seeking to halt the pace of reform, she said that "fiddling changes" would not be sufficient to raise standards.
Sense of mission
Ms Morris said: "What motivates a school to succeed is a bit like individuals - if it has got a sense of its own mission, if it has got a sense of its own purpose and identity, if it knows it is special in some way.
"That's what the diversity agenda is about. It's about saying to schools we want all of you to have a specialism or something about you - a mission statement that makes it different."
Ms Morris denied that this would lead to a two-tier system, as some critics have suggested.
The changes begun under former education secretary David Blunkett would be good for parents and pupils because they gave them "real choice or real expressions of preference," she said. Wary of being seen as overly critical of the teaching profession - which has long complained of being overworked and underpaid - Ms Morris stressed that not all secondary schools and teachers were bad, and many were excellent.
But indicating a commitment to what Labour has in the past called "making tough choices", she said: "It is not good enough and there need to be not just fiddling changes."
Ms Morris said teachers' salaries had improved, and the government had looked at pay incentives to make the profession more attractive.
Her willingness clash with the unions over the introduction of performance-related pay is thought to have contributed to her elevation.
At last year's National Union of Teachers conference she faced a walkout and heckling - but stood firm in pushing through the selective pay system.
Speaking on Sky's Sunday With Adam Boulton programme, Ms Morris admitted that the number of teacher vacancies across the country was "a challenge" that had to be faced.
And she acknowledged the problem had increased but pointed out that it was more than a decade since the teacher recruitment targets had been met.
As well as introducing new incentives to try to get more students into teacher training, the government was now looking at flexibility to tackle shortages, the minister said.
" There never was a golden age where everybody went to higher education free and nobody paid "
And she offered the prospect of part-time teaching courses to make it "as easy as possible" for middle-aged people changing career to study for teaching qualifications - without forcing them to lose the income from their existing jobs.
Ms Morris said she understood why her predecessor had described the introduction of student fees as one of his most difficult decisions.
But she defended the government's controversial decision to abandon free university tuition, arguing that it was necessary for the expansion of higher education.
"There never was a golden age where everybody went to higher education free and nobody paid," she said.
"There were a very small number of students when I went to university who left school, did a three year course and had a grant."