Labour MPs including Jeremy Corbyn are piling pressure on the Tories to do more to help the struggling steel industry after a crunch meeting of the Tata board broke up without a shortlist of bidders for its UK operations being agreed.

Tata Steel had been expected to publish the shortlist after its meeting in Mumbai today but the firm said only that several bids were under “active consideration”.

The uncertainty continues as hundreds of British steelworkers represented by Community, Unite and GMB marched on London to protest at the crisis in the industry.

They were left disappointed after the Tata board meeting – for which Welsh First Minister Carwyn Jones had travelled to India – closed without any clarity.

The firm said it was still evaluating the bids for its British business, which includes sites at Port Talbot, Newport and Rotherham, and was in the “confidential phase of this process”.

It is thought there are seven bidders including Greybull Capital, Liberty House and a Port Talbot management buyout team known as Excalibur Steel.

Tata stopped short of publishing a shortlist today, however, as Labour MPs demanded tougher action from the Tories, who have been painfully slow to react to the crisis.

Stephen Kinnock, whose Aberavon seat includes Port Talbot, said workers had delivered a clear message to Tata and the Tories to “Save Our Steel”.

“The Tata board meeting in Mumbai should have brought greater certainty to the sale process, but we are left pretty much where we were, with no short-list announced. Ending this ongoing uncertainty is essential.

“It is crucial that Tata Steel make good on their promise to be a responsible operator and seller, and that whoever is the owner at the end of this process manages the transition in a manner that will command the loyalty, trust and respect of the workforce.

“That means a clear indication of the long term commitment to investment in Strip Products, the continued operation of the blast furnaces in Port Talbot and a clear and fair settlement on the pensions.

“The Government must also now make every effort to support the UK steel industry by acting on energy costs, procurement and Chinese dumping.”

Kinnock spoke out after Tom Blenkinsop, MP for Middlesborough South and East Cleveland, used PMQs to confront Osborne – filling in for David Cameron – over the crisis.

“Why do the Government back China’s bid for market economy status against the interests of British steelworkers? Why does this Chancellor block changes to the lesser duty tariff against the interests of British steelworkers? When will he set down an industrial strategy to put British steelworkers’ interests ahead of his own?”

Osborne pointed to the “global crisis” in the industry and highlighted Government action including cutting energy charges on energy-intensive industries and “making sure that there are tough tariffs on Chinese dumping”.

Earlier Corbyn had joined marching steelworkers who, he said, had been put through “terrible traumas”.

“This industry is strong. The communities are strong,” he told the BBC.

“The workers are incredibly skilled. They have built everything there is in this country: every road, every railway, every new building is because of steelworkers and the steel industry. They must not be sent down the road. The industry must not be destroyed, and we will make sure it is not destroyed. That’s why we are here today”.