The government is facing calls to speed up moves to regulate the funeral selling industry to protect vulnerable elderly people after a Guardian investigation exposed a firm using high-pressure tactics where staff referred to potential customers as prey.

The Guardian revealed how Prosperous Life – which claims to be one of the country’s leading providers of pre-paid funeral plans – operates a call centre with a culture inspired by the film The Wolf of Wall Street at which staff call themselves “lions” and customers “gazelles” to be hunted.

Multiple former employees at the company detailed how elderly people were subjected to dozens of calls a week and that they felt pressured to push them to sign up for £4,000 funeral plans with little regard for their income.

It comes nearly six months after the Treasury pledged to stamp out unscrupulous practices in the £2bn industry by bringing it under the regulation of the Financial Conduct Authority (FCA). But no action has yet been taken to change the necessary existing legislation which has not been altered for nearly two decades.

Even when the legislation is changed to bring in FCA regulation for pre-paid funeral plans – which allow people to pay for the cost of their funeral before they die in monthly sums – there is set to be an 18-month implementation period meaning more delay.

Rushanara Ali, a prospective Labour MP, who served on the influential Treasury select committee until the election was called, urged the government to speed up regulation to protect vulnerable people.

“After the election, whatever look of government we have, I think there is a need to move quickly to legislate,” she said. “The government announced nearly six months ago that the pre-paid funeral industry would be regulated by the financial conduct authority. Why has it taken so long for this to happen? I can’t see why this issue wouldn’t have cross-party support so that can’t be why there’s been a delay.

“At the moment there is evidence firms are getting away with unscrupulous sales practices and we need to move quickly to protect vulnerable, elderly people. If this sector is not regulated, the consequences are huge on bereaved families. The fact that quicker moves haven’t been made to regulate sends out the wrong message to rogue firms.”

She also called for the Information Commissioner’s Office, which says it is “making enquiries” after receiving multiple complaints about Prosperous Life, to formally investigate the company after the Guardian’s investigation.

James Daley, the managing director of Fairer Finance, a research and ratings agency which produced a report in 2017 calling for the funeral plan industry to be regulated by the FCA, also called for the government to speed up its proposed plans.

He said: “Even when legislation is laid, there’s still a significant amount of work that needs to be done at the FCA’s end to bring this sector under its wings. Probably, we’re looking at the earliest to a year to two years after the legislation is laid and there doesn’t seem to be any prospect of that happening quickly at the moment.

“In the meantime tens of thousands of people continue to get subjected to high-pressure sales and are potentially walking away with plans that aren’t what they thought they were.”

Prosperous Life, which is run by the former premiership rugby club Sale Sharks owner Ian Blackhurst and sells more than 1,000 pre-paid funeral plans a month, denied the whistleblowers’ claims, saying it acted responsibly. The firm, which whistleblowers said sometimes tricked customers into giving personal details to complete customer records, denied it breached the Data Protection Act or contacted people excessively. It said that it responded to specific requests for people to be contacted about funeral plans and did not “knowingly sell to vulnerable customers”.

The ICO said: “We have received a number of complaints about Prosperous Life and we are making enquiries.”

Last month, the Treasury minister John Glen responded to a written question about the timetable to bring in regulation, saying: “The government intends to bring the pre-paid funeral plan market within the remit of the Financial Conduct Authority and has consulted on the proposed legislative framework to implement this proposal. The consultation closed on 25 August and the government is currently reviewing the responses. A response to the consultation will be published in due course.”