Media playback is unsupported on your device Media caption Nicky Morgan's speech was interrupted by hecklers several times

Education Secretary Nicky Morgan has been met with shouts of "rubbish" as she told teachers about plans to turn all schools in England into an academy.

In an address to the NASUWT teachers' conference, Ms Morgan said there was no going back on plans to make every school an academy by 2020.

She also urged the union to take a more positive line about the profession rather than talking of "crisis".

She told teachers she would do more to protect them from online harassment.

Initially applauded when she took to the stage at the gathering in Birmingham, Ms Morgan's speech met with a frosty response from delegates at times.

There was laughter and clapping when she said the government did not always get things right, and one delegate shouted "get off" when she asked teachers to "step up".

Others, though, praised her for coming to speak to teachers at a union conference.

Analysis by BBC Education Editor Branwen Jeffries

It was an uncompromising message from Nicky Morgan to the teachers gathered here.

She told them either they could step up to the challenge of improving education or spend the next four years battling the government.

There was, she said, no reverse gear for the government plans. But Nicky Morgan also recognised their concerns about red tape and workload.

Her speech was heard in a mixture of mainly polite to stony silence and some heckling. At the end there was some polite applause.

Afterwards delegates described her speech as provocative, but many also gave her credit for being brave enough to face an audience of teachers.

'No reverse gear'

Ms Morgan paid tribute to the profession, but said there could be no pulling back from the government's agenda of reform.

The government has announced plans to make every school in England become an academy by 2020.

However, the scheme has met with resistance from opposition parties, teachers' unions and Conservative local councillors.

But Ms Morgan told delegates the government's plans would improve the education system in England.

"I want to be clear [...] there is no reverse gear when it comes to our education reforms."

Ms Morgan also accused the NASUWT of peddling too much negative comment about the state of the profession, teacher retention and recruitment.

"If I were a young person making a decision about my future career and I saw some of the language coming out from the NASUWT as well as some of the other unions, would I want to become a teacher?

"If I read about a profession 'standing on the precipice of a crisis', would I consider a life in teaching? - no I would not."

Ms Morgan went on: "The teaching unions have a choice - spend the next four years doing battle with us and doing down the profession they represent in the process, or stepping up, seizing the opportunities and promise offered by the White Paper and helping us to shape the future of the education system."

Image caption Ms Morgan urged teachers to work with the government on academy plans

It is the first time a Conservative education secretary has addressed the NASUWT conference since 1997.

NASUWT general secretary Chris Keates thanked Ms Morgan for attending the annual gathering and said she would be welcome to attend every year.

But she urged her to abandon imposing the academies system on the remaining local authority-controlled schools in England.

She said: "Don't allow yourself to become the next Iain Duncan Smith; listen to the concerns being raised.

"If you want education excellence everywhere, then recognise there are outstanding academies, outstanding community schools, outstanding foundation schools, outstanding voluntary-aided schools which prove academies do not have the monopoly on excellence."

Image copyright Thinkstock Image caption The NASUWT has raised concerns about the use of social media

Ms Morgan also pledged more support for teachers to protect them from the threat of violence and harassment.

This followed NASUWT's own research, which showed the extent to which teachers are being trolled and abused on social media.

Ms Morgan said she had asked her officials to start work on what more can be done to ensure teachers are better protected, particularly online.

White Paper proposals: