A company behind almost 100 million nuisance calls has been fined a record £400,000 by the Information Commissioner's Office (ICO).
Keurboom Communications Ltd was issued the penalty after more than 1,000 people complained about receiving automated calls.
Calls were made over an 18-month period and related to a wide range of subjects such as PPI compensation and road traffic accident claims.
It did not have the specific consent of the people it was making the automated marketing calls to, meaning it was in breach of the law.
Keurboom Communications Ltd also hid its identity so it was harder for people to complain, the ICO said.
During the investigation, the company - registered in Dunstable, Bedfordshire - was issued with seven information notices ordering it to give information t o the ICO.
Its failure to comply led to Keurboom Communications Ltd and its director Gregory Rudd being fined a total of £2,500, plus costs, at Luton Magistrates' Court in April 2016.
Steve Eckerlsey, head of enforcement at the ICO, said: "Keurboom showed scant regard for the rules, causing upset and distress to people unfortunate enough to be on the receiving end of one its 100 million calls.
"The unprecedented scale of its campaign and Keurboom's failure to co-operate with our investigation has resulted in the largest fine issued by the Information Commissioner for nuisance calls."
He added: "These calls have now stopped - as has Keurboom - but our work has not.
"We'll continue to track down companies that blight people's lives with nuisance calls, texts and emails."
Mike Lordan, director of external affairs at the Direct Marketing Association (DMA), said: "We applaud the work of the Information Commissioner's Office in their work against rogue marketers who do nothing for consumers and give the legitimate industry a bad name.
"We hope that in the future rogue marketers will face the real threat of prison when abusing consumers in this way, which will be an effective deterrent."
Alex Neill, from consumer group Which?, said: " Nuisance calls are a menace, so it's right that the companies making them are held to account and hit with big fines.
"The next Government should swiftly bring in new powers holding directors personally accountable for these unlawful calls."
James Dalton, from the Association of British Insurers, said: " This record fine sends the clear message that nuisance cold-calling is totally unacceptable.
"It is absurd that those responsible for these calls may be able to avoid the fine by shutting down their company and starting another one.
"Tightening up the loopholes exploited by the compensation cowboys cannot happen soon enough."