By Sarah Toyne BBC News Online personal finance reporter

In November, Ken Holly, 58, will have worked at the Tredegar steel plant, in South Wales, for 18 years but the �100 weekly pension he expected to receive when he retires is no longer secure.

Earlier this year, his employer - the Caparo Group - made a decision to close the final salary pension scheme to all workers, and replace it with a cheaper alternative.

People feel very unhappy, as a group of men we feel very bitter

Ken Holly

Caparo's decision is merely one of a growing wave of closures in recent years.

Final salary schemes have traditionally been seen as the gold standard of pensions - the best a worker can get.

But employers are replacing them with cheaper plans, known as "money purchase schemes".

These are much less burdensome for employers, but are more risky for workers.

After a year of escalating closures, workers and unions are beginning to fight back.

Mr Holly told BBC News Online why he had no choice but to join in the industrial action.

Ken Holly: "We can ill afford not to"

"At our level, we can't afford to gamble with our old age pension. People feel very unhappy, as a group of men we feel very bitter," he says.

Workers on strike believe the new scheme is too risky for people who earn between �280 to �330 gross a week, the typical wages at the Tredegar plant, and need a reliable pension.

"We don't want to strike," says Mr Holly.

"We can ill afford it, but the mood is very determined at the moment."

Workers feel Labour has failed to rein-in companies over closures.

Mr Holly is quick to praise local politicians, but he is very disappointed with the government.

"The Labour party is not the most popular thing around. I'm a member, but I'm not very happy with those at a top level," says Mr Holly.

"The government should issue some sort of statement to prevent this sort of thing happening."

This week, ISTC, Mr Holly's union rejected an offer from Caparo and announced it was escalating the level of strikes to two days a week.