Media playback is unsupported on your device Media caption Jeremy Corbyn: "We want railway and Royal Mail in public ownership"

A debate on public ownership of firms is needed, but restoration of "Clause IV" is not a priority, leadership hopeful Jeremy Corbyn has said.

Earlier, he told the Independent on Sunday the party could restore Clause IV, its pledge to common ownership, or set up a similar commitment.

But he told the BBC more discussion was needed, after the leadership vote, to decide the party's economic direction.

Leadership rival Liz Kendall told the IoS Clause IV belonged in the past.

The clause, cementing Labour's commitment to common ownership, was scrapped by then leader Tony Blair in 1995.

'Natural monopolies'

Mr Corbyn told the BBC: "Well I opposed his change then and obviously didn't agree with the wording that he chose. I don't see that as the absolute priority that we're talking about at the moment.

"What I see is the greater democratisation of our party - bottom-up policy making rather than top-down decision-making - and that is what is attracting a lot of people to the Labour party and into this discussion."

He added: "We want our railway system and our Post Office - Royal Mail rather - in public ownership, they are natural monopolies.

"We are looking at the whole question of the energy industry, the excessive profit-taking of the 'big six' and the subsidies we give to the big six and the subsidies we put into nuclear clean-ups."

What was Clause IV?

Image caption An old Labour membership card in the days of Clause IV

A commitment to public ownership of industry was inserted into Labour's constitution in 1918: "To secure for the workers by hand or by brain the full fruits of their industry and the most equitable distribution thereof that may be possible upon the basis of the common ownership of the means of production, distribution and exchange, and the best obtainable system of popular administration and control of each industry or service."

At the time this was seen as Labour's version of the Marxist doctrine that the "means of production" should be placed in the hands of the workers.

In practice, the aim was to nationalise the "commanding heights" of the economy - major industries such as coal, steel, telecommunications and railways, as well as the Bank of England and utilities such as water, gas and electricity.

All of these were taken into state ownership by the 1945 Labour government, although most private companies remained in private hands, as part of a "mixed economy".

The centre-right of the Labour Party waged a long campaign to ditch Clause IV, seeing it as an unrealistic throwback to an era of hard line socialism, arguing that the party was no longer committed to nationalising the entire economy - but it was seen as an article of faith by those on the left.

Tony Blair scrapped Clause IV soon after he became party leader, a move seen by some as a symbolic step which made the party more electable in the post-Margaret Thatcher era.

The original wording was replaced with a new commitment to "a thriving private sector and high-quality public services where those undertakings essential to the common good are either owned by the public or accountable to them".

He said that he was proposing a national investment bank, which would be "investing in new industries, investing in new jobs, investing in sustainable development" and he wanted more co-operatives.

Earlier, he told the IoS: "I think we should talk about what the objectives of the party are, whether that's restoring the Clause IV as it was originally written or it's a different one, but I think we shouldn't shy away from public participation, public investment in industry and public control of the railways."

Analysis by Ben Wright, BBC political correspondent

Mr Corbyn's campaign momentum seems unflagging - to the alarm of senior figures in the party. But he says the party needs a new statement of objectives - and that could be the original Clause IV.

Mr Corbyn has already promised to renationalise energy companies and the railways and increase public spending on industry. One of Mr Corbyn's leadership rivals, Ms Kendall, condemned the idea as a "throwback to the past".

Some party donors are alarmed by the prospect of a Corbyn win too.

Businessman Assem Allam, who donated £300,000 to Labour during the election, has told the Sunday Telegraph he would stop giving money to the party if Mr Corbyn becomes leader, saying he never backed a "dead horse".

Mr Corbyn is one of four candidates standing in next month's Labour leader election, alongside Ms Kendall, Yvette Cooper and Andy Burnham.

Ms Kendall - the leadership challenger seen as being the closest to Mr Blair's policies - fiercely condemned the suggestion that Clause IV could be reintroduced.

"Life has moved on from the old Clause IV in 1994, let alone 2015," she said. "We are a party of the future, not a preservation society."

Fellow leadership contender Yvette Cooper said Labour did not need a return to "the days of British Leyland".

"Labour needs radical ideas for the future, not to turn the clock back," she said.

But former deputy prime minister John Prescott said the suggestion that Clause IV could be revived had echoes of Labour under Tony Blair.

"Tony Blair took the view that it was indicating to the public a change in direction. Now, I think that is what Jeremy is doing here. He's actually announcing it - presumably with the party to decide - and is wanting to show a different direction to which we're going. So in a way it has that kind of ideology which the party will debate and listen to."

Labour leadership contest

Image copyright Getty Images Image caption Labour leadership candidates (l-r): Liz Kendall, Andy Burnham, Yvette Cooper, Jeremy Corbyn.

Who are the candidates? Andy Burnham, Yvette Cooper, Jeremy Corbyn, Liz Kendall

Andy Burnham, Yvette Cooper, Jeremy Corbyn, Liz Kendall Dates: Ballot papers will be sent out on 14 August; voting can take place by post or online. They must be returned by 10 September. The result is on 12 September

Ballot papers will be sent out on 14 August; voting can take place by post or online. They must be returned by 10 September. The result is on 12 September Who can vote? All party members, registered supporters and affiliated supporters - including those joining via a union

All party members, registered supporters and affiliated supporters - including those joining via a union What is the voting system? The Alternative Vote system is being used so voters are asked to rank candidates in order of preference

The Alternative Vote system is being used so voters are asked to rank candidates in order of preference How does it work? If no candidate gets 50% of all votes cast, the candidate in fourth place is eliminated. Their second preference votes are then redistributed among the remaining three. If there is still no winner, the third place candidate is eliminated with their second preferences (or third in the case of votes transferred from the fourth place candidates) redistributed. It is then a head-to-head between the last two candidates

At-a-glance profiles of the four contenders