AFP - Indian steel giant Tata Steel on Wednesday put its British business up for sale, placing thousands of jobs at risk and striking a heavy blow to the crisis-hit steel industry.

Tata said in a statement that trading conditions had "rapidly deteriorated" in Britain and Europe due to a global oversupply of steel, a "significant increase" in cheaper imports into Europe, weak domestic demand, high costs and currency volatility.

"These factors are likely to continue into the future and have significantly impacted the long term competitive position of the UK operations," read the statement issued in Mumbai.

The company's European arm Tata Steel Europe will now "explore all options for portfolio restructuring including the potential divestment of Tata Steel UK, in whole or in parts" -- including Britain's biggest steel plant at Port Talbot in Wales.

"Given the severity of the funding requirement in the foreseeable future, the Tata Steel Europe board will be advised to evaluate and implement the most feasible option in a time-bound manner," it said.

In response to the grim news, the British government urged Tata to allow time to locate a potential buyer.

"We want enough time to be able to secure a buyer. That will take months," said business minister Anna Soubry.

She insisted that Prime Minister David Cameron's Conservative government was considering "all options" and raised the possibility of management and unions being involved in any future plans.

Union representatives had travelled to Mumbai as a company board meeting was held to try to convince Tata to invest in the plants, which employ thousands in England and Wales.

Politician Leanne Wood, leader of Welsh party Plaid Cymru, described the news as "devastating" and called for the Welsh regional assembly to be recalled from its Easter break to respond to the crisis.

Tata had previously announced a series of job cuts at its huge Port Talbot site, where it employs 4,000 people, with another 3,000 employed as contractors and temporary workers.

A joint statement from the British government and the Welsh regional government said they would work with unions to maintain the steel industry.

"This is a difficult time for workers in Port Talbot and across the UK," it said.

"Both the UK and Welsh governments are working tirelessly to look at all viable options to keep a strong British steel industry at the heart of our manufacturing base."

Unions have accused China of killing off British industry by "dumping" steel on the market at prices that cannot be competed with.

Tata said it had poured money into the UK businesses and suffered asset impairments of over £2.0 billion ($2.8 billion, 2.5 billion euros) in the last five years.

Opposition Labour leader Jeremy Corbyn urged Cameron to act "immediately".

"The government must intervene immediately to protect UK jobs and British manufacturing," he said.

Unions meanwhile criticised the government for not sending a minister to India to lobby for the plants to be kept open.

"We are now in the grip of an industrial crisis," said Len McCluskey, general secretary of Unite.

"Decisions taken in the days to come will determine not just the futures of 19,000 workers and their families, across 14 sites, but the very success of this government's own economic programme."

Dave Hulse, national officer of the GMB union, added: "This is absolutely devastating news for all our members, their families and the local communities.

"Tata has let the whole of the UK steel industry down."