Iain Duncan Smith has denied his proposals to reform the controversial Section 28 rule are connected to last year's spat over gay adoption.

The proposal, if adopted, would give legal force to other existing government guidelines on relationship and sex education.

This is our replacement for Section 28 - it's a straight swap Tory source

The guidelines ban pupils from being stigmatised on grounds of sexual orientation, but stress the importance of marriage.

Section 28 bans the promotion of homosexuality by local councils - including in schools - and was introduced when Margaret Thatcher was Tory prime minister.

Free opinions

Speaking on a visit to Wales the current Conservative leader promised his party a free vote on the issue.

He said: "We believe in these sort of areas it's better that people express their free opinions.

"My view all along is that we would probably have a free vote. It's a wholly separate subject from the issue of adoption by unmarried couples."

That was a reference to the row over gay adoption which followed the party leadership's decision to set a three-line whip and force MPs to vote a certain way.

The ensuing spat ended up with Mr Duncan Smith's future being called into question and his "unite or die" appeal to Tory MPs.

The Tory proposal will be tabled in two weeks time as an amendment to the Local Government Bill during a committee stage.

The Tory proposal would force schools to make public to parents any teaching materials used for sex education classes.

Then if a "sufficient number" of parents objected schools would hold a ballot before the materials were put to use in the classroom.

'Genuine protection'

The Conservatives say their proposal would devolve power to schools.

Parents will still have a say on sex education

Local government spokesman David Davis said: "Our number one priority is to offer children genuine protection and to strengthen the rights of parents when it comes to the way children are taught sex in our schools.

"That is what really matters to families up and down the country. It is an important issue that goes beyond party politics."

Section 28 was introduced in 1988 and has become a focal point for equal rights campaigners.

Backing its removal may go some way to modernise the Conservative Party's image.

The Department for Education has expressed doubts as to whether Section 28 could have been used against schools.

Lords hope?

With Labour's huge majority the Tories concede their plan to replace Section 28 may fail in the House of Commons.

It is in the Lords that party sources indicate they feel more optimistic that their plan may be accepted by the government in the face of opposition to reform from peers.

"This is our replacement for Section 28," said a senior Conservative source.

"It's a straight swap."