The U.K’s Royal Mail postal delivery service has been fined £5.6 million ($6.9 million) by the regulator Ofcom for missing its first- and second-class delivery targets.

The Guardian reported November 13 that Ofcom said Royal Mail missed the targets by a “significant and unexplained margin,” causing “considerable harm” to its customers.

The company delivered more than a quarter of first-class post late, with only 74% arriving on time in the 2022-23 financial year, far below its statutory target of 93%.

It also missed its second-class target, delivering 91% on time compared with a target of 98.5%, and its postal workers completed 89% of delivery routes for each required day, short of the 99.9% expectation.

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Royal Mail’s parent company, International Distributions Services (IDS), is owned by investors and listed on the London Stock Exchange’s FTSE 250 index of mid-sized companies. But it still has obligations to deliver mail on time, a legacy from before it was privatized in 2013.

Royal Mail has struggled in recent years as the volume of letters being delivered has declined markedly. That has been exacerbated by poor relations with its workforce, resulting in a series of strikes during its peak period in November and December last year, and a ransomware computer attack in January during which hackers demanded $80 million to decrypt files.

In a statement, Royal Mail said it was “very disappointed” with its performance. It said: “Last year was uniquely challenging for Royal Mail. Quality of service was materially impacted by the long-running industrial dispute which included 18 days of strike action.”