Its stock plunged 17 percent in early trading to a new record low, while rivals also slipped.

Johnston Press, which owns more than 200 local and regional newspapers including The Scotsman and The Yorkshire Post, said trading had been "extremely challenging" in the first five months of the year, with revenue down 9 percent.

It has been reviewing its finances and is in talks with bondholders to refinance 220 million pounds in bonds due on June 1, 2019. It said no agreement has yet been reached and talks were continuing.

"The trading environment remains extremely challenging, exacerbated in recent months by uncertainty around future paper costs and the impact of GDPR on digital advertising revenues," it said.

Britain's newspaper industry has struggled for more than a decade as advertisers and readers moved online, forcing several print publishers including the owner of the Mirror, now called Reach, and the Daily Mail and General Trust to slash costs.

Reach fell nearly 4 percent on Tuesday and the Daily Mail group was down almost 1 percent.

Johnston Press, which lost its CEO Ashley Highfield last month after seven years at the helm, has been trying to restructure. It has also reviewed its property portfolio and cut spending to counter the mounting pressure on sales.

Under Highfield, the company bought "i", the cut-price national sister paper of The Independent two years ago to tap into its circulation revenue and advertising base.

A continued strong performance from the "i" enabled the group to maintain its expectations for the full year.

The General Data Protection Regulation (GDPR) imposes new requirements on how companies collect and process personal information about users in the European Union. That threatens to disrupt online advertising which relies on personal data to send targeted ads to consumers.

Royal Mail warned last month that the new rules may reduce marketing mails.

"We expect to see continued pressure on revenues in the second half of the year, and a requirement for cost savings," Johnston Press said.

(Reporting By Justin George Varghese in Bengaluru; editing by Kate Holton)

By Justin George Varghese