Ed Miliband has come under pressure to bring the rail network back into national ownership if Labour wins the next election, as more than 30 of his party's parliamentary candidates call for a bold new policy to improve services and control train fares.

In a joint letter to the Observer, the prospective MPs – many of whom will fight in marginal seats where they say the commuter vote could be crucial – argue that a policy of gradual renationalisation would allow fares to be kept under control and profits to be reinvested in services.

Their intervention comes as radical options for the future of the rail network are being considered by Labour's lengthy policy review, which is nearing completion. It also coincides with a pledge in the Observer by two key figures in the Labour election team to present the most radical manifesto in a generation.

While Miliband has said he is interested in "innovative solutions" for the railways and is open to considering a greater degree of state control, shadow chancellor Ed Balls is said to be resistant to anything that would be portrayed by Labour's opponents as anti-business or a lurch back to the pre-Thatcher era of nationalised industries.

In their letter, the candidates say a big move on rail ownership and fares could prove a vote-winner on doorsteps, particularly in marginal seats in the south, which Labour must seize if it is to win an overall majority. They argue that under the present franchising system, private companies can charge high fares and "walk away with hundreds of millions of pounds every year, despite running monopoly services and benefiting from £4bn of public investment in the rail network every year".

Instead, they want to extend the system of national ownership that has operated successfully on the East Coast main line since 2009, when the franchise run by National Express failed, and bring all franchises under state control as they come free. "A commitment to extend this successful model to the rest of the rail network, as existing contracts come to an end, would mean that hundreds of millions currently lost in private profit would be available to fully fund a bold offer on rail fares," they say.

The letter, which shows the pressure Miliband is under to deliver more eye-catching policies in areas ranging from health to childcare, goes on: "Labour's response to this should be to offer a fairer deal to commuters as a part of Ed Miliband's response to the cost of living crisis.

"Just as Labour has pledged to freeze energy bills and reset the market to secure a better deal for customers, so it will be necessary to reform the rail industry to secure a better deal for passengers."

On Saturday night one of the signatories, Nancy Platts, who is seeking to overturn a 1,300 Tory majority in Brighton Kemptown, said: "If I can have some concrete policies to sell on the doorsteps, that will make a big difference. Rail fares are a huge issue here and in other commuter areas. For many people who have to buy a season ticket, they are like a second mortgage. Changing the way we run the rail system is an issue of fairness."

An Opinium/Observer poll on the future of rail shows that more than three times as many people back some form of renationalisation of rail services (55%) as oppose it (18%).

When the idea of bringing franchises back under national control as they fall free was put to voters, three times as many Tory voters (60%) backed the idea as opposed it (20%). Among Labour voters 71% were in favour and 8% against.

Writing in the Observer with exactly a year to go until the general election, the chair of the party's election strategy, Douglas Alexander, and campaign co-ordinator, Spencer Livermore, pledge that Labour will deliver "the boldest, most radical, offer in a generation" to the British people to address living standards.

After a week in which the party announced it would intervene in the housing market by putting a ceiling on the amount by which private landlords can raise rents, they say markets must be made to work for those facing cost of living pressures. "It is a crisis that demands we reform the market, while the fiscal problems we will inherit mean we must be reformers of the state too," they write.

Last a week a group of more than 40 Labour MPs met in the House of Commons to discuss Labour policy on rail, and backed steps to bring the system back under a greater degree of state control. The left-of-centre pressure group Compass is also preparing to launch a campaign pushing for franchises to be brought back under state ownership with more transparency and accountability built into the system.

On Sunday, Miliband is expected to raise concerns about the planned takeover of UK drugs firm AstraZeneca by US rival Pfizer, increasing pressure for action to ensure British companies are not left at the mercy of predators by firms from overseas. On Saturday former Labour trade minister Lord Davies warned that British business could suffer if "top industries"were left vulnerable to bids.

He said: "I do wonder whether this deal is more about financial engineering rather than industrial logic."

Labour 'plans alcohol crackdown'

A Labour government would impose tough restrictions on the sale and advertising of alcohol, unhealthy food and tobacco, according to a leaked policy document.

The plan would end sports sponsorship by drinks firms and impose minimum alcohol pricing in an effort to cut the impact of drinking on Britons' health.

There would also be new laws to curb the amount of sugar, fat and salt in food aimed at children, and a ban on advertising unhealthy products on TV before the 9pm watershed.

The Mail on Sunday reported that the plans are contained in a report to the "society" sub-group of the shadow cabinet.

Setting out the reasons for the clampdown on alcohol, the Labour document says: "Up to 35% of all A&E attendances and ambulance costs may be alcohol related and up to 70% at weekend peak times."

There would also be measures to tackle smoking so that "children born in 2015 will become the first smoke-free generation for hundreds of years".

The plan would involve a ban on smoking in cars with children present – a measure that has already been backed by MPs – and the introduction of plain packaging.

A Labour spokesman said the leaked paper "represents a wide range of options" but was not official party policy. Press Association